Lemon-Lavender Cake

INGREDIENTS

• 8 sprigs pesticide-free fresh lavender flowers, or 1 tsp. finely chopped, pesticide-free fresh lavender leaves, plus flowers for deecorating (optional)
• 1 1/4 cups superfine sugar
• 16 Tbs. (2 sticks) unsalted butter, at room temperature
• Finely grated zest of 2 lemons
• Pinch of fine sea salt
• 4 eggs
• 1/2 cup sifted all-purpose flour
• 1 1/2 cups ground blanched almonds
• 1/4 cup fresh lemon juice
• 1 1/2 cups confectioners' sugar
• Juice of 1/2 large lemon, or as needed