In a large bowl or stand mixer fitted with a paddle attachment, cream together butter and sugar on high until light and fluffy.
Add in egg and vanilla and beat until well combined.
In a separate bowl, sift together flour, baking powder, and salt.
Slowly add the flour mixture to the butter mixture, lightly mixing between each addition until flour in completely incorporated.
Roll into a ball, wrap in cling wrap and chill for 1-2 hours.
Preheat oven to 350 F and line baking sheet with parchment paper.
Roll dough out evenly with a lightly floured roller onto a lightly floured flat surface until it's a 1/4 inch thick.
Use the round cookie cutter to cut out cookies.
Use the foot of the dinosaur toy to make a footprint in the cookies.
Transfer to baking sheet and bake for 8-10 minutes, just until edges begin to brown.