Preheat the oven to 350 degrees F. Lightly grease an 8x8 baking sheet, then line with parchment paper and set aside.

In a large bowl, whisk together the flour, oatmeal, brown sugar, cinnamon, baking powder, and salt. Add melted butter to the bowl and mix with a spoon until well combined.

Spread ¾ of the crumble mixture into an even layer in the bottom of the prepared pan. Bake for 10 minutes, then allow to cool.

In another large bowl with a hand mixer, or in a stand mixer, beat the cream cheese and sugar together for 3 minutes until well combined. Add the eggs and vanilla and beat to combine. Add the remaining ingredients and mix until combined, but do not overmix.

Pour the cheesecake batter over the crust in the pan and spread in an even layer. Sprinkle half of the remaining crumble dough over the batter.

Bake for 20 minutes, then carefully sprinkle the remaining crumble over the cheesecake. Bake another 12-18 minutes, or until the cheesecake is just set (the edges will be set, the middle will have a slight wobble to it, but not be liquidy).

Turn off the oven and crack the door, holding it open with the handle of a wooden spoon. Allow cheesecake to slowly cool in oven for 1 hour, then remove and place in refrigerator. Chill 6 hours to overnight until cold before serving.