Prep the pan: Heat oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners. Lightly mist liners with nonstick spray for easy release.

Whisk dry ingredients: In a medium bowl, whisk flour, cornstarch, baking powder, and salt. Set aside.

Rub zest into sugar: In a large bowl, combine sugar and lemon zest. Use your fingers to rub them together until the sugar is fragrant and slightly damp. This boosts lemon flavor.

Combine wet ingredients: Add melted butter, oil, yogurt, eggs, lemon juice, and vanilla to the lemon sugar. Whisk until smooth and creamy.

Fold in dry ingredients: Add the flour mixture to the bowl and gently fold with a spatula just until combined. Do not overmix. The batter will be thick and silky.

Prep the raspberries: Toss raspberries with 1 teaspoon of flour. This helps keep them from sinking.

Stir in berries: Fold raspberries into the batter with 3–4 gentle turns. Keep some berries intact for juicy pockets.

Fill the liners: Divide batter evenly among liners, about 3/4 full. Tap the pan once on the counter to release air bubbles.

Bake: Bake 18–22 minutes, or until the tops spring back and a toothpick comes out with a few moist crumbs (avoid poking a berry pocket).

Optional lemon soak: While warm, brush tops with a quick syrup made from 2 tablespoons lemon juice mixed with 2 tablespoons sugar (stir until dissolved). This adds tang and keeps them moist.

Cool completely: Let cupcakes cool in the pan 5 minutes, then transfer to a rack to cool fully before glazing.

Make the glaze: Whisk powdered sugar with 1–2 tablespoons lemon juice and a splash of milk or cream until thick but pourable. Adjust to your preferred consistency.

Finish with fresh berries: Spoon glaze over cooled cupcakes. Top with a few fresh berries and an extra pinch of lemon zest, if you like.