In a small bowl mix flour, salt, and baking powder together; set aside.
Add 1 1/2 cups animal cookies to a quart-sized baggie and crush using a rolling pin or hand until cookies are crumbly and there are no big chunks of cookie left; set aside.
In a stand mixer using the paddle attachment, cream the butter and sugar until light in color and fluffy, about 3-4 minutes on high.
Add eggs one at a time, mixing on low for 10 seconds in between each addition, then add vanilla.
Add half of the flour mixture and mix until just combined. Add all of the milk and mix until just combined. Lastly, add the other half of the flour mixture, mixing on low speed until combined.
Gently fold in the crushed cookies.
Fill cupcake liners 3/4 of the way full into your prepared muffin tins.
Bake cupcakes for 18-20 min, rotating halfway through baking and pulling out of the oven when a toothpick comes out clean.
Let cupcakes cool halfway still in pan before transferring to a wire rack.
Let cupcakes cool completely before frosting.
VANILLA FROSTING
Put 2 sticks softened butter in a stand mixer with the paddle attachment. Beat on high for 4 minutes until fluffy. Add 6 cups powdered sugar, 1/2 cup milk, and 1 teaspoon vanilla (and food color if using) to mixer and mix on low speed for 30 seconds, then increase speed to high until frosting is smooth. Add additional powdered sugar if needed to get desired consistency
Once I frosted the cupcakes, I sprinkled some nonpareils on top and topped each cupcake with an animal cookie :) ENJOY!