½ cup unsalted butter, at room temperature 1¼ cups sugar 2 teaspoons lemon thyme, finely chopped 4 teaspoons grated lemon peel 3 eggs 1 teaspoon vanilla extract 2 cups all-purpose flour ½ teaspoon baking soda 1 teaspoon baking powder ½ teaspoon salt ¾ cup sour cream ½ cup confectioner’s sugar ½ cup lemon juice
Preheat oven to 350° F. Grease a loaf pan and dust with flour. Cream together butter and sugar in an electric mixer until light and fluffy. Add lemon thyme, grated lemon peel, eggs, and vanilla and mix well. Stir together the flour, baking soda, baking powder, and salt. Add dry ingredients to the butter-sugar mixture alternately with sour cream and blend. Pour batter into pan and bake for approximately one hour.
Place the confectioner’s sugar in a bowl. Gradually whisk in the lemon juice. Brush the top of the hot cake with some of the mixture. Let stand for 10 minutes, then brush the entire cake with the mixture. Repeat again after 10 minutes.