Pour layers slowly over the back of a spoon to avoid breaking the layer below. Chill each layer until firm but not fully hard before adding the next to prevent color bleeding. Use room temperature condensed milk for better mixing. For dairy-free options, substitute sweetened condensed milk with canned coconut milk mixed with maple syrup or almond milk-based condensed milk alternatives. Layers can be prepared up to two days in advance and stored refrigerated in an airtight container. Avoid freezing as gelatin texture changes.