In a medium bowl, beat the butter and granulated sugar until smooth and creamy. Mix in the vanilla extract and milk until combined.

Add the flour and cocoa powder, folding until a thick, edible brownie batter forms. Set aside.

Add the semi-sweet chocolate chips to a microwave-safe bowl. Melt in 30-second intervals, stirring between each, until fully smooth. Mix in pink food coloring until your desired shade is reached.

Spoon 1–2 tablespoons of melted chocolate into each heart mold. Use the back of a spoon to spread the chocolate evenly along the bottom and sides.

Place the molds in the refrigerator to chill for 15–30 minutes, or until the chocolate is fully set. Reserve the remaining melted chocolate for later.

Once the chocolate shells are firm, add about 2 tablespoons of brownie batter filling to each mold, gently pressing it in.

Reheat the reserved chocolate until smooth. Spoon about 1 tablespoon of chocolate over each truffle to fully seal the filling.

Return the molds to the refrigerator and chill for 30 minutes, or until completely set.

Carefully remove the truffles from the molds and decorate with your favorite toppings if desired. Enjoy immediately, or store in an airtight container in the refrigerator for up to 8 days.