For the Cupcakes:1 cup (240 ml) (8 oz) buttermilk, at room temperature
2 eggs + 1 egg yolk, at room temperature
1/4 teaspoon (1.25 ml) pure vanilla extract
2 cups (230 g) cake flour, sifted
1-1/4 cups (250 g) granulated sugar
1-1/2 teaspoon (8 g) baking powder
1/2 teaspoon (2 g) baking soda
1/4 teaspoon (2 g) salt
1/2 cup (1 stick) (115 grams) unsalted butter, at room temperature
Finely grated lemon zest (rind) of two medium-large lemons
For the Frosting:
3 sticks (340 g) unsalted butter, softened and cut into cubes
3.5 cups (400 g) confectioners’ sugar, sifted
3 tablespoons (45 ml) whipping cream (35% cream), or whole milk
1 tablespoon dried Culinary Lavender
1 teaspoon (5 ml) pure vanilla extract
a pinch of salt