Melt the Fats: In a small saucepan or microwave-safe bowl, gently melt the butter and coconut oil together over low heat. Stir occasionally to blend the fats into a smooth mixture.
Mix the Ingredients: In a medium mixing bowl, combine the cooled espresso, cocoa powder (if using), powdered sweetener, vanilla extract, and sea salt. Slowly pour in the melted butter and coconut oil mixture. Stir until everything is well combined. If you're using heavy cream, add it now for extra richness.
Pour into Molds: Pour the mixture into silicone molds (small cupcake liners or ice cube trays also work). You can adjust the size of each bomb depending on how much you want to snack on.
Chill: Place the molds in the freezer for 30-45 minutes, or until the bombs have fully set.
Serve: Pop the bombs out of the molds and enjoy! Store any leftovers in the fridge or freezer for when you need a quick snack.