I saw a mix for this cake at World Market, and decided I needed to make one for myself. Be sure to get food-grade lavender blossoms. I order mine from MySpiceSage.com. They are very reasonable. A one-ounce bag equals about 2-3 cups in volume.
Preheat oven to 325°F. Grease a 9x5” loaf pan and dust lightly with flour.
With an electric mixer, cream the butter well. Then cream in the sugar until fluffy and well blended. Beat eggs in one at a time, beating well after each addition. Add vanilla.
Sift together the cake flour, buttermilk powder, cream of tartar, and salt. Add the flour mixture to the creamed mixture a little at a time, alternating with the buttermilk, mixing slowly until thoroughly blended. Fold in lavender blossoms.
Spread batter in prepared pan, and bake about 55-60 minutes, until tester or toothpick inserted in center comes out clean.
Cool cake 10 minutes in pan, then remove and finish cooling on wire rack.