Heat oven to 350 degrees F.
In a large bowl of a food processor fitted with blade attachment, combine flour, brown sugar and 2 teaspoons cinnamon. Pulse until well combined.
Add butter slowly, pulsing between additions, until pea-sized pieces form.
Press 1/2 of the mixture in an ungreased 9-inch springform pan; set remaining mixture aside.
Place apples, stevia, cornstarch, and remaining 1 teaspoon cinnamon in a large bowl; stir to combine. Place apples in prepared springform pan. Evenly sprinkle the remaining mixture over apples.
Place springform pan on baking sheet with sides. Bake 60–70 minutes until top is golden.
Remove from oven. Run knife around the edge of pan; let cake cool completely. Remove springform ring just before serving.
https://www.thedailymeal.com/recipes/apple-pie-streusel-cake-recipe