Almond Buttercream Frosting 

1. In the bowl of your stand mixer, combine your unsalted butter, powdered sugar, vanilla extract, heavy cream, and salt. Start mixing on a low setting in short spurts to incorporate and avoid powder flying everywhere. Then increase speed and beat for another 5 minutes.
2. Taste test and add lemon juice if too sweet for your liking. Thin it out as needed with another tablespoon or two of heavy cream.
3. Once happy with flavor, use a spatula to smooth the frosting. Drag the spatula from the middle of your bowl to its edges, watching as the tears and bubbles in your buttercream disappear. Spend 3-4 minutes doing these motions to achieve nice, smooth frosting.

Frosting & Piping Your Buttercream Lemon Cake

Begin decorating once your cake layers are fully baked and cool to the touch.

1. Color the buttercream. Divide the buttercream evenly into four small bowls. Leave one bowl white. Add yellow food coloring to the other three bowls and mix well. To create variation, add a small amount of red food coloring to one yellow bowl and a small amount of blue food coloring to another, mixing until evenly combined.
2. Prepare the cake layers. Add a small dollop of buttercream to the center of your cake circle or cake board to act as glue. Place the first cake layer on top, then spread a thin, even layer of buttercream over the surface of the cake.
3. Stack the cake. Place the second cake layer on top of the first. Add additional buttercream between the layers as needed, spreading it evenly and filling in any gaps so the layers are level and secure.
4. Apply the base coat of frosting. Starting at the bottom of the cake and working upward, pipe a thick layer of buttercream around the sides of the cake. Continue piping buttercream over the top of the cake to fully cover it.
5. Smooth the sides. Hold a cake scraper (or the back of a bench scraper) against the side of the cake and gently rotate the cake to smooth out air bubbles and excess frosting.
6. Finish the top edge and chill. Continue smoothing until the cake is fully coated and even. Using a standard or small offset spatula, push the excess buttercream from the top edge (it will resemble a small crown 👑) toward the center of the cake. Transfer the cake to the refrigerator and chill for 30 minutes to allow the frosting to set.
7. Sketch the design. Once the buttercream has set, use a toothpick to lightly sketch your design directly onto the cake. Outline lemon shapes, leaves, and any additional decorative elements before piping.
8. Pipe the lemons. Fit a piping bag with a round piping tip and fill it with yellow buttercream. Pipe the lemon shapes by first outlining each lemon, then filling it in completely. The design may look slightly rough at this stage — it will be smoothed later.
9. Pipe the leaves. Fit a second piping bag with a round piping tip and fill it with green buttercream. Pipe leaf shapes around the lemons, varying their size and direction for a natural look.
10. Fill in the design. Continue alternating between the yellow and green piping bags, piping additional lemons and leaves until the design feels balanced and the blank space is filled to your liking.
11. Chill again. Place the cake back into the refrigerator briefly to firm up the piped buttercream, which will make smoothing easier.
12. Smooth and refine. Use the back of a spoon or an offset spatula to gently smooth out any blemishes or rough areas in the piped buttercream. Work carefully to maintain the shape of the lemons and leaves while achieving a clean, polished finish.