Apple Streusel Sheet Cake

Ingredients

• 3 Count Granny Smith apples - 3 medium (about 1 lb), About 1 lb total; peel, core, and dice into 1/2-inch pieces.
• 2.5 Cup all-purpose flour - 2 1/2 cups (300 g), divided, 300 g total; divided between streusel and cake batter.
• 0.75 Cup unsalted butter, melted - 3/4 cup (170 g), divided, 170 g total; divided between streusel and cake batter.
• 0.75 Cup light brown sugar, packed - 3/4 cup (165 g), divided, 165 g total; packed and divided between streusel and cake batter.
• 0.75 Cup granulated sugar - 3/4 cup (150 g), Used in the cake batter.
• 2 Each large eggs - 2 (count)
• 0.5 Cup whole milk - 1/2 cup (120 ml), 120 ml total.
• 2 Teaspoon vanilla extract - 2 tsp (10 ml), 10 ml total.
• 2 Teaspoon baking powder - 2 tsp (8 g), 8 g total.
• 2 Teaspoon ground cinnamon - 2 tsp (5 g), divided, 5 g total; divided between streusel and cake batter.
• 0.75 Teaspoon fine salt - 3/4 tsp (4 g), divided, 4 g total; divided between streusel and cake batter.

Instructions

1. Preheat and prep apples

   1. Preheat the oven to *350°F* and line a *9x13-inch baking pan* with parchment paper. Peel, core, and dice the *Granny Smith apples* into *1/2-inch pieces*.

2. Make the streusel

   2. Make the streusel: in a medium bowl, stir *3/4 cup flour*, *1/2 cup light brown sugar*, 1 tsp cinnamon, and 1/4 tsp salt with *1/4 cup melted butter* until *coarse crumbs* form.

3. Mix the wet ingredients

   3. In a large bowl, whisk the remaining *1/2 cup melted butter*, granulated sugar, and remaining *1/4 cup light brown sugar* until combined. Whisk in the *eggs*, milk, and vanilla until *smooth and glossy*.

4. Combine the batter

   4. In another bowl, whisk the remaining *1 3/4 cups flour*, baking powder, remaining *1 tsp cinnamon*, and remaining 1/2 tsp salt. Stir the dry mixture into the wet mixture until *no dry streaks remain*; *do not overmix*.

5. Fold in apples and pan the batter

   5. Fold in the *diced apples* with a rubber spatula until *evenly distributed*. Scrape the batter into the pan and *spread it level*.

6. Add the streusel

   6. Scatter the *streusel topping* evenly over the batter, gently pressing only the largest crumbs so they *stick lightly* to the surface.

7. Bake the cake

   7. Bake for *33 to 38 minutes*, until the top is *golden brown* and a toothpick inserted in the center *comes out clean*.

8. Cool, slice, and serve

   8. Cool the cake in the pan on a wire rack for *at least 20 minutes*. Lift out, slice into *12 squares*, and serve.