Heat oven to 375°F. Line a 12-cup muffin pan with paper liners and lightly mist with spray.
Beat cream cheese with powdered sugar and 0.5 tsp vanilla until smooth; refrigerate while you prep the batter.
Whisk flour, granulated sugar, brown sugar, baking powder, baking soda, salt, and cornstarch in a large bowl.
Combine buttermilk, Greek yogurt, oil, remaining 1.5 tsp vanilla, and lemon zest in a separate bowl until smooth.
Stir wet mixture into dry ingredients just until no dry streaks remain. Do not overmix.
Fold in diced strawberries gently to keep the batter light.
Scoop a heaping tablespoon of batter into each cup. Add a rounded teaspoon of cream cheese mixture, then cover with more batter to fill about 3/4 full.
Sprinkle tops with turbinado sugar. Bake 18–21 minutes, until golden and a tester comes out clean around the cream cheese.
Cool in the pan for 5 minutes, then transfer to a rack to finish cooling. Serve warm or at room temperature.