This Lavender Lemon Cake is two layers of light, moist lemon cake with a smooth and silky lavender buttercream! The textures and flavors of this beauty are a masterpiece!
Preheat oven to 350° F. Grease two 8-inch round cake pans and set aside.
In a medium bowl, combine the dry ingredients (flour, baking powder, baking soda, and salt). Set aside.
In the bowl of a stand mixer, combine the sugar and lemon zest. Be sure to only include the yellow part of the rind, and not the white pith underneath, as it is bitter.
Run the mixer on low for a few minutes to allow the oils from the lemon to infuse the sugar.
Add the butter and cream the mixture together on medium speed until light and fluffy, at least three minutes. Scrape down the sides of the bowl as needed.
Add the eggs one at a time, allowing the first egg to incorporate before adding the second. Scrape down the sides of the bowl again.
Add the lemon extract paste (see note) and lemon juice. Mix briefly to combine.
Alternate adding the dry ingredients with the milk: with the mixer on low, gradually add half the dry ingredients, followed by the milk, then the remaining dry ingredients. Mix just until incorporated, taking care not to overmix.
Divide the batter evenly among the prepared pans (see note). Bake until lightly golden on the edges and a toothpick inserted in the center comes out clean, or with a few moist crumbs attached, 20-25 minutes. Allow the cakes to cool ten minutes in the pans before removing to a wire rack to cool completely.
For Buttercream:
In a medium saucepan, combine milk, cream, and dried lavender (see note).
Over medium heat, warm until just beginning to simmer. Remove from the heat and let cool to room temperature. Refrigerate the mixture for at least two hours (up to overnight). Once chilled, use a fine mesh strainer to strain the lavender from the mixture.
In a medium saucepan, combine the sugar, flour, and salt. Whisk to combine. Add the milk mixture and whisk until combined. I like to add the milk gradually, whisking as I go, to help ensure the custard won't have lumps.
Cook the mixture over medium heat, stirring constantly, until the mixture has thickened, 10-15 minutes.
Transfer the custard to the bowl of a stand mixer and mix on medium speed with the whisk attachment until the mixture cools to room temperature, about 20 minutes. Alternatively, you can also cool the mixture to room temperature in the refrigerator, which will take 30-40 minutes.
Once the custard is at room temperature, beat with the whisk attachment, adding the butter a few pieces at a time. Allow the butter pieces to incorporate before adding more. Add vanilla bean paste (see note) and mix to combine. Beat buttercream on medium speed another 4-5 minutes, or until light and fluffy.
Frost the cooled cake layers with the buttercream, and top with fresh lemon slices and dried lavender, if desired.Enjoy!
Notes
Note on lemon extract paste: For a punch of lemon flavor without adding much liquid! If you'd like, you can substitute with an equal measure of lemon extract.Note on cake pans: This recipe is for a two-layer 8" cake. I suggest using 8" pans that are light in color to avoid overbaking the cakes (as darker pans bake the cake faster).Note on kitchen scale: To ensure I have the same amount of batter in each pan, I use my kitchen scale and weigh the pans/batter.Note on lavender: You'll want to make sure that you're using culinary lavender, since other lavenders aren't meant to be eaten and could have been sprayed with harmful chemicals. I bought my lavender here.Note on vanilla bean paste: Vanilla bean paste is fabulous for another layer of flavor and beautiful black specks of vanilla bean in your buttercream! If you'd prefer, you can substitute with an equal measure of vanilla extract.