Brussels Sprouts Garlic Parmesan Casserole

Picture a bubbling casserole, edges caramelized and golden, with emerald Brussels sprouts tucked into a velvety, garlicky cream that perfumes the kitchen like a cozy hug.

Imagine the contrast: tender sprouts cloaked in silky sauce, a crisp Parmesan-panko lid that shatters gently under your fork, and a whisper of lemon zest to lift every bite. This is comfort with character—vegetables transformed into something craveable and celebratory.

I first baked this on a rushed weeknight when groceries were scarce and spirits lower; it turned a bag of sprouts into a table-gathering moment, and my family asked for seconds before I’d sat down.

It’s dependable for busy weeknights or Sunday suppers, elegant enough for holidays, and friendly to make-ahead plans when you’re juggling guests or homework. Whether you’re feeding four or stretching leftovers, it delivers warmth, texture, and ease in one pan. Ready? Let’s cook!

Why You’ll Love It

• Delivers bold, garlicky Parmesan cream with cozy crunch
• Streamlines prep with quick blanch-and-bake method
• Balances richness with bright lemon zest and parsley
• Scales easily for holidays and weeknight dinners
• Welcomes add-ins like bacon or pancetta for smokiness

Ingredients

• 2 lb Brussels sprouts trimmed and halved — choose firm, bright green heads
• 2 tbsp kosher salt for blanching water — seasons sprouts throughout
• 2 tbsp unsalted butter — adds richness to the sauce
• 1 tbsp olive oil — helps bloom garlic without burning
• 6 cloves garlic minced — fresh cloves give best aroma
• 1/2 tsp crushed red pepper flakes optional — adjust heat to taste
• 1 cup heavy cream — for a silky, clingy sauce
• 1/2 cup whole milk — lightens the cream slightly
• 1 tsp Dijon mustard — subtle tang to balance richness
• 1/2 tsp kosher salt — season the sauce
• 1/2 tsp black pepper freshly ground — adds gentle bite
• 3/4 cup Parmesan cheese finely grated, divided — use real Parmigiano-Reggiano
• 1/2 cup mozzarella cheese shredded — low-moisture melts smoothly
• 1/2 cup panko breadcrumbs — for a crisp, airy topping
• 1 tbsp fresh parsley chopped — bright, fresh finish
• 1 tsp lemon zest finely grated — lifts the flavors with citrus aroma

Step-by-Step Method

Preheat the Oven and Prep the Dish

Preheat oven to 400°F (200°C). Lightly grease a 9×13-inch baking dish with cooking spray or a thin film of oil. Set it aside. Gather all equipment and measure ingredients. This guarantees a smooth workflow and accurate timing. Position an oven rack in the center for even baking and browning.

Blanch the Brussels Sprouts

Bring a large pot of water to a rolling boil. Add 2 tablespoons kosher salt, then the trimmed, halved Brussels sprouts.

Blanch 3 to 4 minutes until bright green and slightly tender. Don’t overcook. Drain immediately in a colander to stop cooking and maintain texture and color.

Dry the Sprouts Thoroughly

Spread the drained Brussels sprouts on a clean kitchen towel. Pat dry well and let stand 2 minutes to release steam.

Remove as much surface moisture as possible. This step helps the creamy sauce cling to the sprouts and prevents the casserole from becoming watery during baking.

Bloom the Aromatics

Heat butter and olive oil in a large skillet over medium heat. Add minced garlic and optional red pepper flakes.

Cook 30 to 60 seconds until fragrant, stirring constantly. Don’t brown the garlic. Blooming the aromatics in fat builds a deeper base flavor for the sauce that follows.

Build and Thicken the Cream Sauce

Whisk in heavy cream, whole milk, Dijon, kosher salt, and black pepper. Bring to a gentle simmer.

Cook 2 minutes, whisking occasionally, until slightly thickened. Avoid a hard boil. The sauce should lightly coat the back of a spoon. Taste and adjust seasoning before adding cheese.

Melt in the Cheeses

Reduce heat to low. Stir in 1/2 cup finely grated Parmesan and the shredded mozzarella.

Mix until fully melted and smooth. Keep the sauce silky by stirring steadily. If it thickens too much, loosen with a splash of milk. The result should be creamy and pourable.

Fold in the Brussels Sprouts

Add the dried Brussels sprouts to the skillet. Fold gently to coat evenly with the cheese sauce.

Guarantee every piece is covered but intact. Maintain low heat to keep the sauce fluid. This even coating is key to a cohesive casserole with consistent flavor in every bite.

Assemble in the Baking Dish

Transfer the creamy sprouts mixture to the prepared baking dish. Spread into an even layer using a wooden spoon.

Smooth the surface for uniform baking. Scrape the skillet to capture all the sauce. This guarantees no dry pockets and promotes even bubbling during the oven time.

Mix the Crunchy Topping

In a bowl, combine panko, remaining 1/4 cup Parmesan, chopped parsley, and lemon zest. Toss to distribute evenly.

Sprinkle the mixture over the casserole in a uniform layer. The combo adds brightness and texture, contrasting the rich sauce beneath. Don’t press down.

Cover, Bake, and Brown

Loosely tent the dish with foil. Bake 15 minutes covered to heat through. Remove foil and bake 10 to 12 minutes more until bubbling and golden on top.

For extra browning, broil 1 to 2 minutes, watching closely. The topping should be crisp and the edges lightly caramelized.

Rest and Serve

Remove from the oven and let the casserole rest 5 minutes. This allows the sauce to settle and thicken slightly for cleaner servings.

Slice into portions and serve hot. Pair with roasted meats or poultry. Store leftovers covered in the refrigerator and reheat to re-crisp the topping.

Ingredient Swaps

• Dairy-light: Use half-and-half instead of cream + milk; for lighter, use evaporated milk. For dairy-free, swap full-fat coconut milk or oat cream, vegan butter, and vegan mozz/parmesan.
• Gluten-free: Replace panko with gluten-free panko or crushed pork rinds/almonds; verify Dijon is GF.
• Lower lactose: Use lactose-free half-and-half and aged lactose-free Parmesan; sub mozz with lactose-free melting cheese.
• Budget: Replace Parmesan with Grana Padano or pecorino blend; use regular breadcrumbs; skip lemon zest or use a splash of vinegar.
• Regional/availability: Swap Brussels sprouts with broccoli florets or halved green beans (adjust blanch time); use yellow mustard if Dijon isn’t available.
• Extra flavor: Add crisp bacon/pancetta or smoked paprika instead of red pepper flakes; sub parsley with chives or thyme.

You Must Know

Doneness • If the topping isn’t evenly golden after the timer, move the dish to the top rack and give it a 1–2 minute broiler pass; stop when panko is deep golden and the sauce visibly bubbles at the edges to make certain set, not soupy.

Troubleshoot • When the casserole looks watery after blanching, pat sprouts completely dry and reduce the cream base on the stovetop by an extra 2–3 minutes until it coats a spoon; excess surface moisture dilutes thickening.

Flavor Boost • For deeper savor, toss the sprouts with 1–2 teaspoons soy sauce or Worcestershire before saucing; the glutamates amplify Parmesan notes without extra salt—taste for salinity after 5 minutes of carryover.

Swap • If using half-and-half only, add 1 teaspoon cornstarch whisked into the dairy before heating; it tightens the sauce to a nappe consistency in about 2 minutes of gentle bubbling so it sets under crumbs.

Scale • For 8–10 servings in a 9×13 that’s heaped, increase ingredients by 50% and extend covered time by 5 minutes; visual cue is vigorous bubbling across the center and an instant-read of 190–200°F in the sauce for full thickening.

Serving Tips

• Serve alongside roast chicken, pork loin, or seared salmon for balance.
• Add a squeeze of lemon and extra Parmesan just before serving.
• Plate in warm bowls; garnish with parsley and cracked black pepper.
• Pair with a crisp Chardonnay or citrusy IPA to cut richness.
• Offer crusty bread to scoop up the creamy sauce.

Storage & Make-Ahead

Refrigerate leftovers in an airtight container 3–4 days.

Reheat covered at 350°F until hot and topping re-crisps.

Assemble up to the breadcrumb step 24 hours ahead, cover, and bake 5–10 minutes longer from cold.

Freezing isn’t ideal due to dairy separation, but tightly wrapped portions freeze up to 2 months.

Reheating

For gentle reheating, cover portions to retain moisture.

Oven: 350°F, 10–12 minutes.

Microwave: 50% power, 60–90 seconds, stirring.

Stovetop: low heat, splash of milk, covered, until warmed through.

Midwest Holiday Potlucks

Often, I carry this Brussels sprouts casserole into a Midwest holiday potluck and watch the room bloom with butter-and-garlic warmth. The church basement hums—mittens steaming on radiators, crockpots singing low.

Your plate fills with ham slices, cheesy potatoes, ribbons of cranberry, and then my bubbling bake lands beside them, crisp panko whispering when the spoon breaks through.

I blanch the sprouts so they stay bright, then swaddle them in cream, Dijon, and melting Parmesan—comfort with a gentle kick. Folks lean in, ask about the lemon zest, nod at the parsley flecks like pine needles on snow.

It travels well, holds heat, and scoops clean. When the casserole comes back scraped, I tuck the warm dish under my arm, heart full as the room.

Final Thoughts

Ready to plunge in? Give this cozy Brussels Sprouts Casserole a try as written, or tweak it with crisp bacon, extra heat, or your favorite cheese to make it your own!

Frequently Asked Questions

Can I Make This Casserole Dairy-Free Without Sacrificing Creaminess?

Yes—you can. I’d swap in full‑fat coconut milk and oat cream, whisk in Dijon and nutritional yeast, and finish with olive‑oil‑toasted panko. You’ll taste velvety richness, nutty depth, and a golden, crackling crown—no dairy needed.

How Do I Scale the Recipe for a Crowd or Smaller Gathering?

I scale it linearly: halve for three, double for twelve, triple for eighteen. Use multiple pans to avoid crowding. Keep blanch times constant, bake until bubbling and golden. Taste salt, adjust. Let it rest; aromas bloom.

What Wines Pair Best With This Rich, Cheesy Side?

I’d pour crisp Chardonnay or Champagne; they slice through richness like sunlight. I also love Grüner Veltliner’s peppery snap, Sauvignon Blanc’s citrus zing, or Pinot Noir’s silky cherry. Each sip brightens cream, kisses garlic, and lifts Parmesan.

Are There Gluten-Free Breadcrumb Alternatives That Stay Crispy?

Yes—use crushed pork rinds, toasted almond flour with grated Parmesan, or gluten-free panko. I toss them in melted butter, lemon zest, and parsley; they shatter like golden snow, staying crisp even under creamy heat.

How Can I Add Heat Without Overpowering the Brussels Sprouts?

I add gentle heat with crushed red pepper and a whisper of Calabrian chili paste. I bloom them in butter and garlic—warmth blooms, not burns—then finish with lemon zest to lift without smothering.