1. Preheat the oven to 350°F and grease a 9×13-inch baking pan.

2. In a medium bowl, whisk together the flour, baking powder, and salt.

3. In a large bowl, beat the butter and 1 1/2 cups granulated sugar until light and fluffy.

4. Add the eggs one at a time, then mix in the vanilla extract.

5. Add the dry ingredients in batches, alternating with the milk, and mix just until combined.

6. Spread the batter evenly into the prepared pan and bake for 28 to 34 minutes, or until a toothpick inserted in the center comes out clean.

7. Let the cake cool completely in the pan.

8. In a saucepan, combine 3 cups chopped strawberries, lemon juice, cornstarch, and 2 tablespoons granulated sugar over medium heat.

9. Cook the strawberry mixture until the berries soften and the juices thicken, then let it cool completely.

10. In a chilled bowl, whip the heavy cream with the powdered sugar until soft to medium peaks form.

11. Spread the cooled strawberry layer over the cooled cake.

12. Top with the whipped cream and finish with the remaining 1 cup fresh strawberries.

13. Chill for at least 30 minutes before slicing and serving.