Place the chocolate in a microwave safe bowl, and melt until smooth and creamy.
Stir well and spoon or ladle into the heart molds making sure to coat the inside of the molds.
Pour excess chocolate back into the bowl and place the molds in the refrigerator and let harden for 15 minutes. Remove molds from refrigerator and carefully remove chocolate from molds placing 6 hearts in a row. (These will be the bottom half of the chocolate bombs.
Heat a non-stick skillet, on low, and place one heart with the open side down, melting just the edges.
Remove, place on a cookie sheet, and fill the heart with the powdered Cocoa, M&M's, and mini Marshmallows. Repeat, until all 6 hearts are done.
Place the other half of the chocolate hearts in the skillet, with the open side down, and melt just the edges of the heart and immediately place on one of the chocolate hearts, making the top of the heart.
Hold in place a few seconds to make sure the top and bottom are melted together.
Place the white chocolate in a microwave safe bowl and microwave at 15 second intervals until the chocolate melts.
Stir well and place the melted chocolate in a pastry bag, and pipe the chocolate over the hearts and sprinkle with Valentines Sprinkles.
Place Hearts in the bottom of a large mug, and pour heated milk over the heart.
Heart will melt and bubble, and marshmallows will float to the top.
Stir the powdered cocoa, and Enjoy!