Preheat the oven to 375 (F) -- this is a 50 degree (F) increase from the original, sea-level recipe temperature of 325 (F).
Put the flour, sugar, baking powder, salt, and butter in a freestanding electric mixer with a paddle attachment (or use a handheld electric whisk) and beat on slow speed until you get a sandy consistency and everything is combined.
Pour in the milk and vanilla and beat on medium speed until all the ingredients are well mixed, making sure to scrape any unmixed ingredients from the side of the bowl with a rubber spatula.
Add the egg to the batter and beat well for a few minutes to ensure the ingredients are well incorporated.
Divide the chopped strawberries between the paper cases in the muffin tray. Spoon the batter until two-thirds full and bake in the preheated oven for 25-30 minutes, or until light golden and the cake tops bounce back when touched. A skewer inserted in the center should come out clean.
Let the cupcakes cool slightly in the pan before turning out onto a wire rack to cool completely.
Roughly break up the graham cracker cookies and put them in a food processor. Process until finely ground.
When the cupcakes are cold, spoon the cream cheese frosting on top and finish with a sprinkling of ground cookies.