Preheat and Prep: Preheat oven to 350°F (175°C). Grease and flour three 8-inch round cake pans or line with parchment for easy removal.
Mix Dry Ingredients: In a medium bowl, whisk 2 1/2 cups flour, 2 1/2 tsp baking powder, and 1/2 tsp salt. Set aside.
Cream Butter and Sugar: In a large bowl, use a hand or stand mixer to cream 3/4 cup softened butter and 2 cups sugar on medium speed for 3-5 minutes until light and fluffy, scraping the bowl as needed.
Add Eggs and Vanilla: Add 4 eggs one at a time, beating well after each. Mix in 1 tsp vanilla extract.
Combine Wet and Dry: Gradually add the flour mixture to the butter mixture, alternating with 1 cup milk (start and end with flour). Mix until just combined to avoid overmixing
Add Fruit Flavors: Gently fold in 1 cup strawberry puree, 1/4 cup lemon juice, and zest of 1 lemon until evenly mixed.
Bake the Cakes: Divide batter evenly among the three pans, smoothing the tops. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean. Cool in pans for 10 minutes, then transfer to a wire rack to cool completely.
Make the Frosting: Beat 1 cup softened butter until creamy. Gradually add 4 cups powdered sugar, mixing until smooth. Add 1/4 cup heavy cream, 1/4 cup strawberry puree, 2 tbsp lemon juice, and 1 tsp vanilla extract. Beat until fluffy, adding more cream if needed. Optionally, add a drop of pink food coloring for a vibrant Strawberry Lemonade hue.
Assemble the Cake: Place one cake layer on a serving platter and spread with frosting. Add the second layer, frost, and top with the third layer. Frost the top and sides, smoothing with a spatula for a polished Lemonade Cake look.
Garnish and Serve: Decorate with halved strawberries and lemon slices for a fresh, summery vibe. Slice and serve, enjoying the bright Strawberry Lemonade Cake flavors.