Step 1

Spray a 9X13 inch baking dish with nonstick cooking spray; Set aside. Preheat the oven to 350 degrees.

Step 2

In a large bowl, using a hand-held electric mixer, cream together the butter and granulated sugar until light and fluffy. Add in the eggs one at a time, mixing until yellow disappears. Mix in vanilla.

Step 3

In a separate bowl, whisk together flour, cinnamon, baking powder, baking soda, and salt. Add to cream mixture alternating with the sour cream until well combined.

Step 4

Add flour mixture to butter mixture alternating with the sour cream until well combined. Fold in the apples.

Step 5

Pour batter into the prepared baking dish, spread evenly with an offset spatula.

Step 6

Bake in preheated oven for 20 minutes.

Step 7

Meanwhile, make the Topping. Whisk together both sugars, cinnamon, nutmeg, and salt until combined. Add warm melted butter and stir until combined.

Step 8

Add flour and mix with fork until clumps form (topping should look a bit wet). Set aside.

Step 9

Remove cake from oven and spread crumb topping clumps (don't press them down) evenly over partially baked coffee cake, covering completely. Topping will be thick.

Step 10

Return to oven and bake until a toothpick inserted in the center comes out with just a few moist crumbs (not batter). About 20-25 minutes.

Step 11

Cool on wire rack at least 30 minutes.