In a medium bowl, whip the softened butter. Add in 1 cup of powdered sugar and mix until combined. Incorporate vanilla and gradually add more powdered sugar. Add 1 Tablespoon of heavy cream or milk for a thick, creamy frosting.n2. In a large bowl, crumble the cooled prepared cake into fine crumbs. Mix in 2 spoonfuls of the buttercream frosting. Combine until the mixture holds together well without being too crumbly.n3. Roll the cake mixture into balls using a medium cookie scoop or your hands and place them on a plate. Freeze for about 10 minutes.n4. Melt dark and white chocolate in separate microwave-safe bowls, heating for 30 seconds at a time and stirring until smooth.n5. Dip each lollipop stick into the melted chocolate and then into the center of each cake pop. Return to the fridge or freezer until the chocolate is set.n6. Dip each cake pop into the melted chocolate, then gently tap to remove excess. Decorate with sprinkles or other toppings before the chocolate hardens.n7. Insert each stick into a styrofoam block or a glass filled with rice to hold them upright. Allow chocolate to set completely (about an hour). Store in an airtight container for 3-4 days.