Preheat your oven to 350°F (175°C) and grease a 9×13-inch sheet pan.
Tip: Line with parchment for easy lifting and clean edges.

Combine dry ingredients in a large bowl: flour, sugar, baking soda, and salt. Whisk well to prevent lumps.

Cook the strawberry mixture. In a saucepan, melt butter over medium heat. Add chopped strawberries and strawberry purée. Bring to a gentle simmer, stirring often.

Pour hot mixture over dry ingredients. Stir gently until just combined. This method helps bloom the strawberry flavor throughout the batter.

Add eggs, sour cream, and vanilla. Mix until smooth, being careful not to overmix.

Spread batter evenly into the prepared pan and tap gently to remove air bubbles.

Bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean.

Cool completely before frosting. This ensures the frosting sets beautifully.