Add flour, baking soda and salt into medium bowl. Stir in the lavender. Using electric mixer, or kitchen aid, beat butter in large bowl at medium speed until fluffy. Gradually add sugar and beat 5 minutes. Add egg one at a time, beating just until combined. Make sure to incorporate all of the butter evenly. Beat in lemon juice and zest. Using rubber spatula, gently fold in dry ingredients. Fold in sour cream. Transfer batter to prepared pans, and bake about 20-30 minutes for minutes or until a toothpick comes out clean Let cakes cool completely before turning out onto cooling racks.