Use gel food coloring for a vibrant red without thinning the batter, and avoid overmixing the cake to keep it tender. Ensure the pudding is fully chilled and thick; if it seems loose, whisk in an extra teaspoon of cornstarch slurry over low heat until it bubbles. A frosting dam is crucial to prevent the pudding from oozing—make it tall and sturdy. If transporting, chill the cake for at least 2 hours and keep it cool. For tidy slices, heat a knife under hot water, wipe dry, and cut with gentle downward strokes.