Step 1

Preheat oven to 375 degrees Fahrenheit. Line a 13x9-inch baking dish with parchment paper that hangs over the edges.

Step 2

For the apples: In a large bowl, toss the diced apples with the brown sugar, cornstarch, cinnamon, and lemon juice. Let macerate (release juices) for 5 minutes.

Step 3

Melt 6 Tbsp of butter in a large sauté pan. Add the apples with their juices, and cook for 10 minutes or until fork tender. Allow apples to cool slightly.

Step 4

For the crust/topping: Using the paddle attachment fitted on a stand mixer, stir flour, sugar, baking powder, and salt together.

Step 5

Add cold butter one Tablespoon at a time, while the mixer is running, until the mixture resembles fine crumbs. Add egg and mix until the dough comes together, in large crumbs.

Step 6

Press ⅔ of the mixture evenly onto the bottom of the prepared 13x9-inch baking dish for the crust. Spread the cooked apples evenly on top, then crumble the remaining crust/topping over the apples.

Step 7

Bake at 375˚F for 25-35 minutes until the top is lightly brown and the filling is slightly bubbling in the center. Allow to cool completely. Use parchment paper to pull bars out of pan for cutting and serving. Cover and store at room temperature.