PREP: Preheat the oven to 350°F (175°C). Lightly grease a 9x13-inch ceramic or glass baking dish. Avoid using a metal pan--it can give the fruit a metallic taste.
APPLE FILLING: In a large pot, toss the cubed apples with cornstarch. Add the remaining filling ingredients. Cook over medium to medium-high heat, stirring consistently for about 5 minutes, until the apples are slightly softened but still retain their shape. Transfer and spread the filling into the greased pan and bake for 10 minutes.
CRUMBLE TOPPING: Ensure the melted butter has cooled to room temperature to prevent the sugar from making the mixture greasy. Combine melted butter with the rest of crumble ingredients. Stir until just combined and mixture resembles crumbles. If it's too wet, add an additional 2-3 tablespoons of flour. Once prepared, sprinkle the crumble mixture over the partially baked apple filling without pressing it down.
CRUNCHY TOPPING: In a separate bowl, mix the crunchy topping ingredients. Sprinkle this mixture evenly over the crumble layer.
BAKE: Place the dish back in the oven and bake for an additional 45-50 minutes, or until the topping is a golden brown and the sides are bubbling.
ENJOY: Remove from the oven and allow it to sit for 20-30 minutes. This resting period allows for the cobbler thicken. Serve warm, paired with fresh whipped cream or vanilla bean ice cream.
Notes
Note 1: Apples: I recommend an equal mix of Granny Smith and Honeycrisp apples. Weigh before peeling to get 3 pounds. Once peeled and cubed, there should be 8 cups. This is about 7-8 apples