Let’s bake this vibrant Strawberry Lemon Cake! First, prepare your oven and pans. Preheat the oven to 170°C (340°F) for a conventional oven. Prepare three 8-inch round cake pans by greasing them well, lining the bottoms with parchment paper circles, and lightly greasing the parchment too. Set aside. Ensure butter, eggs, sour cream, and milk (for frosting) are at room temperature.

Prepare the dry ingredients for the cake. In a large bowl, sift together the all-purpose flour, cornstarch, baking powder, baking soda, and salt. Whisk well to combine. Set aside.

Infuse the sugar with lemon zest. In another large mixing bowl (preferably your stand mixer bowl), add the granulated sugar and the freshly grated lemon zest. Use your fingertips to rub the zest into the sugar until the sugar becomes fragrant and looks like damp, pale yellow sand. This releases the lemon oils for maximum flavor.

Cream the butter and sugar-zest mixture. Add the room temperature butter to the lemon sugar. Using the paddle attachment of your stand mixer (or a handheld mixer), beat the butter and lemon sugar together on medium-high speed for a full 3 minutes until light, fluffy, and pale in color. Scrape down the sides of the bowl.

Add the room temperature eggs, two at a time, to the creamed mixture. Beat on low speed after adding each pair, just until combined. Scrape the bowl again.

Combine remaining wet ingredients. In a separate small bowl or measuring cup, whisk together the room temperature sour cream, vegetable oil, fresh lemon juice, and vanilla extract until smooth.

Alternate additions. With the mixer on low speed, add about half of the sifted dry ingredients to the butter/egg mixture. Mix until just barely combined (still streaky). Add all of the sour cream mixture and mix on low until just combined. Add the remaining half of the dry ingredients and mix on low speed only until the flour is just incorporated. Do not overmix.

Give the batter a final gentle fold with a rubber spatula, scraping from the bottom, to ensure all ingredients are combined without deflating the batter.

Divide the finished cake batter evenly among the three prepared 8-inch cake pans. Smooth the tops gently with an offset spatula. Bake in the preheated oven for 20-23 minutes. The recipe notes the cakes will stay light and won’t brown much. They are done when a wooden toothpick or cake tester inserted into the center comes out clean.

Let the cakes cool in their pans on wire racks for 10 minutes. Then, carefully run a thin knife or offset spatula around the edges to loosen and gently remove the cakes from the tins. Let the cakes cool completely on the wire racks before frosting.

While the cakes cool, make the Strawberry Buttercream. Sift the powdered sugar and the freeze-dried strawberry powder together into a bowl to remove lumps and combine them well. Set aside.

In a large bowl using a stand mixer with the paddle attachment (or a handheld mixer), beat the room temperature butter on medium-high speed for a full 4 minutes until it is very pale, smooth, and fluffy. Scrape down the sides and bottom of the bowl, then beat for an additional 2 minutes. This long beating time incorporates air for a light frosting.

Turn the mixer speed down to low. Add the sifted powdered sugar/strawberry powder mixture in two parts (about half each time). Add the vanilla extract and 2 tablespoons of room temperature milk along with the sugar additions (e.g., add half sugar mix, 1 tbsp milk + vanilla, mix; add rest of sugar mix, 1 tbsp milk, mix). Mix on low until just incorporated after each addition.

Once all ingredients are added, increase the speed to medium-high and beat for another 2-3 minutes until the buttercream is very light, fluffy, and smooth. Add the optional drop of food coloring now if desired for a brighter pink. Check consistency: if too stiff, beat in more room temperature milk, 1 teaspoon at a time. If too soft (unlikely), beat in more sifted powdered sugar. Give the finished buttercream a final mix on low speed for 2 minutes to push out large air bubbles for smoother frosting.

Assemble the cake once layers are completely cool. Level the tops if needed. Place the first cake layer on your serving dish or turntable. Add about 2 large scoops of strawberry buttercream and use an offset spatula to spread it evenly over the layer. Place the second cake layer on top and repeat with another layer of buttercream. Place the third and final cake layer on top (upside down for a flat top).

Apply a thin crumb coat of the strawberry buttercream all over the cake (top and sides) to trap any loose crumbs. Place the cake in the refrigerator for 20 minutes to set the crumb coat. Add the remaining buttercream to the outside of the cake, smoothing the top and sides with your offset spatula. Optionally, create a wavy or textured design using the spatula as desired.

Decorate the finished cake with fresh strawberries (halved or whole) and thin lemon slices just before serving.