Cut your sugar cookie dough into 12 equal pieces and place them about 2 inches apart on a greased baking sheet.
Bake according to your package instructions.
After fully baked, remove the cookies from the oven. While still warm, use a glass to quickly create a rim inside the edge of each cookie. (you don't have to do this but I find it helpful to create a line for piping later).
Remove each cookie to a cooling rack and allow them to completely cool before decorating.
Prepare your icing by filling a freezer bag with the frosting and cutting a small piece out the the tip of the bag to pipe. (I fitted my freezer bag with a Wilton 1A tip for a more fun design). Also, if you want to make different colored frosting, simply divide the white frosting into small bowls and mix in the food coloring of your choice and pipe using multiple bags.
Pipe a dollop in the middle of each cookie, then following the circular indentation you made with the cup, pipe a design around the edge
Place one dot in the center of the dolloped icing to create the top of the sombrero. Then toss your sprinkles all over the frosted areas!