Devil's Food Cake with Chocolate-Orange Buttercream

INGREDIENTS

2 tsp

Lavender, dried blossoms

1 tbsp

Orange peel

Eggs, large

1 1/2 cups

All purpose flour

1 tsp

Baking powder

1/4 tsp

Baking soda

8 oz

Chocolate, bittersweet or semisweet

Chocolate curls

1 cup

Cocoa powder, unsweetened

1 1/2 cups

Golden brown sugar, packed

1 tsp

Kosher salt, coarse

4 cups

Powdered sugar

2 tsp

Vanilla extract

2 1/4 cups

Butter, unsalted

1/2 cup

Whole milk

1/2 cup

Whole-milk yogurt, plain

1 tbsp

Grand marnier or other orange liqueur

7 tbsp

Water

4 ounces bittersweet (not unsweetened) or semisweet chocolate, chopped