Preheat the oven to 350º F. Add the butter and sugar to a stand mixer and beat for 3 minutes, or until it becomes light and fluffy.
Scrape down the sides of the bowl. Then add the egg and vanilla extract and mix until fully incorporated.
In a separate bowl, mix the flour, baking powder and salt together. Then, add it to the bowl of the stand mixer and mix until it forms a loose dough.
Place the dough onto a clean surface and knead it until it forms a ball. If the dough is sticky, you can lightly flour the surface and your hands (I didn’t use any flour). Then, take a small piece of dough and form a rough ball. Flatten it with your hands until it’s 1/4″ thick. (Keep the edges rough looking to make the fossil look more realistic.) Place it onto a cookie sheet lined with parchment paper or silpat, and repeat until all the dough is used up. Make sure to place the cookies at least an inch apart.
Bake for 6-8 minutes. As soon as they come out of the oven, use your dinosaurs to make fossil imprints. Make sure to press the dinosaur down firmly (but gentle enough to not break the cookie), and roll it around a bit to capture all of the details.
Mix a little bit of cinnamon and sugar together. Then, brush the mixture into the fossil imprints to make them “pop.” Once the cookies are firm enough to move, transfer them to a cooling rack. Store them in an airtight container after that have completely cooled. Enjoy!