Preheat the oven to 350 degrees. Use convection bake if you have it.
Add softened butter and softened cream cheese to a large mixing bowl and use a hand or stand mixer to beat until smooth. Scrape the bowl down once complete
Add in brown sugar and granulated sugar. Mix until smooth.
Add graham cracker crumbs, egg and vanilla extract. Mix until smooth and scrape the bowl down once complete.
In a separate bowl, whisk together flour, baking powder and salt. Then add it to the wet ingredients in 2 to 3 portions, mixing well after each addition.
Use a large cookie scoop or large spoon to place 3-inch cookie dough balls on to a greased cookie sheet (or line it with parchment paper). Leave at least 2 inches in between each cookie.
Bake for 20-25 minutes or until the bottoms and tops of the cookies have begun to brown.
While the cookies are baking, make the key lime pie filling (instructions below).
Remove them from the oven and use a tablespoon or the back of a cookie scoop to make indents in each of the cookies (pictured above). Allow the cookies to cool to for 5 minutes before adding the strawberry pie filling.