Preheat oven to 375°F. Line a standard muffin tin with paper liners and set aside.
Toss blueberries with 1½ tablespoons flour to prevent sinking. Set aside.
In a medium bowl, whisk together flour, cornstarch, baking powder, cinnamon, and salt.
In a large bowl, whisk oil, melted butter, and sugar. Add eggs, then milk and vanilla.
Add dry ingredients to wet and stir until just combined. Fold in blueberries gently.
In a separate bowl, whisk cream cheese, sugar, egg yolk, and vanilla until smooth.
Make streusel by mixing flour, brown sugar, butter, and salt until crumbly.
Spoon batter into liners two-thirds full. Top with cream cheese, swirl, and sprinkle streusel.
Bake for 25 minutes or until a toothpick comes out clean. Cool for 15 minutes before serving.