In a medium bowl, stir together flour, baking powder and salt, if desired. Set aside.
In large mixing bowl at medium speed, beat together butter and sugar until light and fluffy. Beat in eggs, yogurt and extract until well blended. Reduce mixer speed to low. Add reserved flour mixture, 1/2 cup at a time, beating just until blended.
Spread evenly in greased and floured 9 x 5 x 3-inch loaf pan. Bake in preheated 325°F (160°C) oven until cake tester inserted near center comes out clean, about 70 minutes. Cool on wire rack 10 minutes. Remove from pan and cool completely.
Makes 1 (9x5x3 inch) loaf, 8 servings.
Source: American Egg Board
Date: April 3, 2003