Preheating and Tin Preparation: Initiate by preheating the oven to 350 degrees Fahrenheit. Concurrently, grease a 24-cup mini-muffin tin to facilitate the removal of the bites post-baking.
Apple Filling Preparation: In a medium-sized pan, melt butter over medium-high heat. Add the diced apples, cinnamon, nutmeg, brown sugar, and 3 tablespoons of water. Cook for approximately 4-6 minutes, or until the apples are slightly softened.
Filling Thickening Process: In a separate small dish, blend cornstarch with 2 tablespoons of water to create a slurry. Introduce this mixture to the pan, stirring continuously. Continue to cook until the apples are tender and the filling has thickened, which should take an additional 4-5 minutes. Allow the mixture to cool.
Crust Mixture Creation: In a large bowl, mix together the all-purpose flour, rolled oats, and brown sugar. Incorporate the softened butter into the dry ingredients using a pastry cutter, continuing until the mixture attains a coarse, crumb-like texture.
Assembling the Bites: Place a heaping tablespoon of the crust mixture into each cup of the mini muffin tin, pressing it down along the bottom and sides to form a cup shape. Reserve the remaining crust mixture for later use.
Filling the Crust Cups: Add approximately 1 tablespoon of the apple filling into each crust cup. Sprinkle about 1 teaspoon of the remaining crust mixture over the apple filling in each cup.
Baking Process: Bake the assembled bites in the preheated oven until they achieve a golden brown coloration, which should take about 15 to 20 minutes.
Cooling and Serving: After baking, allow the bites to cool in the pan for 10 minutes. Utilize a knife to gently loosen the bites from the tin. They should detach readily. If desired, drizzle the tops of the bites with caramel topping prior to serving.