Preheat your oven to 350°F (175°C). Combine rolled oats, all-purpose flour, granulated sugar, and melted butter until crumbly. Press this mixture into the bottom of a greased springform pan. Bake for about 10 minutes.

In a large bowl, beat the cream cheese until smooth. Gradually add granulated sugar and sour cream, blending until creamy. Incorporate the eggs one by one, mixing well after each addition.

Peel, core, and slice the apples, then toss with cinnamon and nutmeg. Spread the apple slices evenly over the cheesecake filling.

Prepare the crumble topping by mixing together oats, flour, sugar, and softened butter. Sprinkle this mixture over the layer of apples.

Bake for approximately 60 to 70 minutes, until the edges are set but the center has a slight jiggle. The aroma will fill your kitchen.

Let the cheesecake cool at room temperature for about an hour. Then refrigerate for at least 2 hours to set.