01 - Preheat oven to 375°F. Grease a mini muffin tin or line with paper liners.
02 - In a skillet over medium heat, melt unsalted butter. Add diced apple, light brown sugar, and ground cinnamon. Stir occasionally until apples are tender and caramelized, about 4 to 5 minutes. Transfer mixture to a bowl to cool.
03 - In a large mixing bowl, whisk together all-purpose flour, granulated sugar, baking powder, salt, and ground cinnamon.
04 - Cut cold butter into the dry mixture using a pastry cutter or fork until the mixture resembles coarse crumbs.
05 - In a separate bowl, whisk together whole milk, egg, and vanilla extract.
06 - Pour the milk, egg, and vanilla mixture into the dry ingredients and gently stir until just combined. Avoid overmixing.
07 - Gently fold the cooled caramelized apple mixture into the batter.
08 - Scoop the batter into the prepared mini muffin tin, filling each cup approximately three-quarters full.
09 - Bake for 16 to 18 minutes, or until golden and a toothpick inserted into the center comes out clean. Allow to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
10 - Once cooled, insert a cake pop stick into the base of each muffin.
11 - Drizzle each muffin pop with caramel sauce. Prepare the glaze by mixing powdered sugar with enough milk to achieve a thick yet pourable consistency and drizzle over pops. Immediately top with rainbow sprinkles. Let set before serving.