Do not overbake to maintain moistness; stop baking when a toothpick comes out with moist crumbs and top springs back when pressed., Use softened butter for smoother frosting; cold butter will cause lumps., Use the ‘spoon and level’ method when measuring flour to avoid packing and resulting dry cake., Jimmies sprinkles are preferred inside the batter as they bleed less color., Can substitute milk with plant-based alternatives 1:1; full-fat milk provides best richness., Egg white usage keeps cake light and perfectly sized for one ramekin; whole egg can be used but reduce liquid slightly if batter feels too loose., Sprinkles can be swapped with sanding sugar or pastel nonpareils if preferred., Recipe can be doubled to bake two ramekins or poured into muffin tins for mini cakes; adjust baking time as smaller portions bake faster., Cake can be stored at room temperature (covered) for up to 1 day, refrigerated for 4-5 days, or frozen unfrosted for up to two months., Freeze frosted cakes is not recommended as it dulls sprinkle topping; freeze unfrosted and frost after thawing., Reheat in microwave for 8-15 seconds or oven at 300°F (150°C) for 5-8 minutes, allowing frosted cake to come to room temperature first if refrigerated.