Slice the butter into pieces and place in a light-colored skillet or saucepan. (Light colored helps you determine when the butter begins browning.) Melt the butter over medium heat, stirring occasionally. Once melted, the butter will begin to foam. Keep stirring occasionally. After 5-8 minutes, the butter will begin browning—you’ll notice lightly browned specks begin to form at the bottom of the pan and it will have a nutty aroma. Once browned, remove from heat immediately and pour into a shallow bowl. Cover tightly, place in the refrigerator or freezer, and chill until solid, about 45 to 60 minutes.

As the butter chills, whisk the remaining streusel topping ingredients together in a medium bowl. Place uncovered in the refrigerator until you need it.

Preheat the oven to 350°F (177°C). Lightly grease a deep-dish 9-inch pie dish, 9-inch square pan, 10-inch cast iron skillet, or any 2–3-quart baking dish. Set aside.

Gently mix all of the filling ingredients together in a large bowl, then spread into the baking dish.

Remove the streusel topping mixture and solidified butter from the refrigerator. Scrape butter out of the bowl and add to the streusel. Cut in the butter using a pastry cutter or forks until the mixture is crumbly. Sprinkle evenly over filling.

Bake for 45–50 minutes until the topping is golden brown and the fruit juices are bubbling around the edges. Remove from the oven, place on a cooling rack, and allow to cool for a few minutes before serving warm. You can also serve room temperature or cold.

Cover leftovers and store in the refrigerator for up to 5 days.