Mix cake batter according to the box’s directions. Add gel food coloring and mix until batter is completely tinted.
Scoop into a muffin tin, lined with paper liners and bake according to the package’s directions.
Allow to cool completely before baking.
While the cupcakes cool, prepare the buttercream: In a large bowl, beat together butter, confectioners’ sugar and milk with an electric mixer. Start on low and gradually increase to high.
Once the ingredients are well-combined and form semi-stiff peaks, scoop into a piping bag with Wilton tip #21 attached.
Frost each cupcake.
Line a pan with wax paper. Knead rolling fondant until smooth.
Roll 24 fondant spheres, about one inch in size each.
To create a heart, press the bottom two fondant spheres together, pointing it at the end. Repeat to create 12 fondant hearts and set aside on half of the wax-paper-lined pan.
Line up 12 pretzel sticks on lined pan. In a small bowl, microwave pink candy melts in 30-second intervals, stirring between each interval.