Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish, making sure the corners are well coated to prevent sticking.
In a medium saucepan, combine the sliced strawberries, granulated sugar, and cornstarch. Cook over medium heat, stirring frequently, until the mixture thickens and becomes glossy — about 5–7 minutes. The strawberries should release their juices, creating a rich, syrupy consistency.
Pour the strawberry mixture evenly into the bottom of the prepared baking dish. Use a spatula to spread it smoothly across the surface.
2️⃣ Make the Cake Batter
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt until evenly combined. This ensures the leavening agent and sugar are well distributed throughout the dry ingredients.
Add the melted butter, milk, eggs, and vanilla extract to the dry ingredients. Stir gently until the batter is smooth and thick, but do not overmix — this helps maintain a tender crumb once baked.
