01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper and lightly grease the surface.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl until evenly distributed.
03 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, approximately 3 minutes. Add eggs one at a time, mixing thoroughly after each addition. Stir in vanilla extract.
04 - Alternate adding dry ingredients and milk to the creamed mixture, beginning and ending with flour mixture. Mix until just incorporated, being careful not to overmix.
05 - Spread batter evenly in prepared pan. Bake for 22 to 25 minutes until a toothpick inserted in the center emerges clean. Cool completely in the pan on a wire rack.
06 - Combine sliced strawberries, granulated sugar, and lemon juice in a bowl. Let stand for at least 20 minutes to allow fruit to macerate and release juices.
07 - Whip cold heavy cream, powdered sugar, and vanilla extract in a chilled bowl until medium-stiff peaks form.
08 - Spread whipped cream evenly over completely cooled cake. Distribute macerated strawberries and their juices over the cream layer.
09 - Slice into portions and serve immediately, or refrigerate until ready to serve.