Ingredients:
For the blueberry sauce:
1 ½ cups fresh or frozen blueberries 
¼ cup granulated sugar 
1 tbsp lemon juice 
1 tbsp cornstarch mixed with 2 tbsp water
For the cheesecake swirl:
8 oz (225g) cream cheese, softened 
¼ cup granulated sugar
1 large egg 
1 tsp vanilla extract
For the cake:
1 ¾ cups all-purpose flour
1 tsp baking powder
½ tsp baking soda
¼ tsp salt 
½ cup unsalted butter, softened 
¾ cup granulated sugar
2 large eggs
1 tsp vanilla extract
¾ cup buttermilk 
Instructions:
Prepare the blueberry sauce:In a saucepan over medium heat, combine blueberries, sugar, and lemon juice. Cook, stirring occasionally, until the berries release their juices (about 5 minutes).
Add the cornstarch slurry and stir until the sauce thickens. Remove from heat and let cool completely.
Make the cheesecake swirl:Beat the cream cheese, sugar, egg, and vanilla extract in a bowl until smooth and creamy. Set aside.
Prepare the cake batter:Preheat oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In a large bowl, beat the butter and sugar until fluffy. Add eggs one at a time, followed by vanilla extract.
Gradually add the dry ingredients to the butter mixture, alternating with buttermilk, starting and ending with the dry ingredients. Mix until just combined.
Assemble the cake:Pour half the cake batter into the pan, spreading it evenly. Add spoonfuls of the cheesecake mixture and blueberry sauce on top, swirling lightly with a knife.
Repeat with the remaining batter, cheesecake mixture, and blueberry sauce, swirling the top for a marbled effect. 
Bake:Bake for 45-55 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
Serve:Slice and enjoy on its own or with whipped cream for a decadent dessert. 
Prep Time: 30 min | Cook Time: 50 min | Total Time: ~1 hr 20 min
Calories: ~340 Kcal per slice | Servings: 10-12 slices