Combine vanilla ice cream, almond milk, and "cake mix" in a blender and pulse until combined. Add 1 cup of birthday cake cubes and 3 tablespoons sprinkles and pulse just until combined. Scrape the blizzards into glasses and top with additional sprinkles and cake cubes if desired. Serve immediately
Cake/Cupcakes + Frosting:
Preheat oven to 350° F(180° C) and combine butter and sugar in large mixing bowl and beat until smooth. Beat in coconut milk, lemon juice, salt, vanilla, and baking powder. Add flour and stir until smooth then stir in sprinkles.
Grease and flour a 6-count cupcake pan or a 5x9 inch loaf pan. Pour batter into pan (divide evenly between slots if using cupcake pan). Bake for 15 - 18 minutes or until toothpick comes out clean. Remove from oven and allow to cool.
Frosting:
Beat butter (or shortening) in a large mixing bowl until creamed. Add vanilla, salt, and powdered sugar a half cup at a time. Add milk beat until light and fluffy. Add a little more milk if needed for a smoother consistency.
When cake is cooled, cut it lengthwise down the center and spread the frosting on one half. Place second half on top and then spread remaining frosting over the rest of the cake. Put the cake in an airtight container and place in freezer to chill until very cold. After at least 1 hour remove cake from freezer and chop into cubes, then return to freezer until ready to use.
Alternatively, if making in cupcakes, you can frost the cupcakes with a pastry bag or a spatula as you would normally frost them. The basic idea is to get chunks of frozen frosting without it getting blended into the blizzard too much. [Another option is to keep the cake and frosting completely separate; Just spread frosting on a cutting board and freeze until solid, then chop into chunks and mix evenly together with cooled and frozen cake cubes.