Preheat oven to 350 F. Coat an 8x8" pan with cooking spray. In large bowl, place first 5 ingredients and mix with a whisk. In medium bowl, place eggs, sugar, yogurt, butter, lemon peel and vanilla and whisk. Pour egg mixture into dry mixture and blend together. Pour into prepared pan and bake 20 minutes or until toothpick comes out clean. Options: Mix berries with a bit of sugar and serve over pieces of cake with whipped cream. Serve warm with vanilla ice cream and a sprinkle of toasted coconut. Serve warm with a little maple syrup and whipped cream. Serve warm and buttered as a side to hearty soup like ham and beans (in this case add a little less sugar and lemon).