Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.

Make the graham cracker crust by combining crushed graham crackers, sugar, cinnamon, and melted butter in a bowl. Stir until the crumbs are fully moistened.

Spoon about a tablespoon of the mixture into each muffin liner. Press it firmly down to form an even base. Bake for 5 minutes, then remove from oven.

For the crumble topping, mix together flour, quick oats, brown sugar, cinnamon, nutmeg, and melted butter in a bowl. Stir until combined and set aside.

Prepare the cheesecake filling by beating the softened cream cheese and sugar until light and fluffy. Mix in eggs one at a time, followed by the sour cream and vanilla. Scrape down the bowl as needed.

For the blueberry layer, toss blueberries with sugar, flour, and lemon juice. Set aside.

Divide the cheesecake filling evenly over the pre-baked crusts, filling about two-thirds full.

Spoon a generous teaspoon of the blueberry mixture over each cheesecake, gently pressing some blueberries into the batter.

Sprinkle each mini cheesecake with the prepared crumble topping, covering the tops evenly.

Bake for 20–24 minutes, or until the centers look almost set (they should jiggle slightly but not be wet).

Remove from the oven and allow cheesecakes to cool in the pan. Transfer to the refrigerator and chill at least 2 hours before serving to set.