For best texture and flavor, be sure the spinach is squeezed as dry as possible so the dip doesn’t become watery, and give it at least a couple of hours in the fridge (or even overnight) so the Knorr mix fully hydrates and seasons the dip. Adjust thickness by adding a little extra mayo if it seems too stiff or a spoonful of sour cream if it’s too thick, and taste just before serving to tweak salt or acidity with a pinch of salt or a squeeze of lemon juice if desired. This dip keeps well for up to 2–3 days refrigerated, so you can make it ahead; simply stir before serving and refresh with a few sliced green onions on top for color and crunch.