1-First Step: Prepare the crust Preheat oven to 350°F. Crush 2 cups Oreo cookie crumbs and mix with 5 tbsp melted unsalted butter. Press firmly into the pan bottom. Bake 10 minutes until set, then cool completely. This base supports the filling without crumbling. For gluten-free, use certified cookies.

2-Second Step: Make the filling Lower oven to 325°F. Beat 16 oz softened full-fat cream cheese and 1/2 cup granulated sugar until smooth, about 2 minutes. Add 2 large eggs one at a time, mixing well. Stir in 1 tsp vanilla extract and 1/2 cup sour cream for tang. Vegan option: swap eggs and use plant-based dairy. Scrape bowl often for even texture.

3-Third Step: Add Nutella swirl Divide 1/2 cup Nutella; warm half slightly for easier swirling. Pour filling over cooled crust. Dollop Nutella on top and swirl gently with a knife for pretty patterns. Avoid overmixing to keep distinct swirls. This step defines the creamy nutella swirl cheesecake appeal.

4-Fourth Step: Bake the bars Bake 35-40 minutes until edges are set but center jiggles slightly. Turn off oven, crack door, and cool 1 hour inside to prevent cracks. Room temperature cool next, then chill 4 hours or overnight. Patience yields perfect slices.

5-Final Step: Finish and serve Lift from pan, drizzle with extra melted Nutella, sprinkle chopped hazelnuts and flaky sea salt. Cut into 16 bars. Serve chilled. For no-bake fans, see variations below. Pairs with coffee or as party bites.