1. Preheat oven to 350°F.
2. In a bowl, whisk together first 4 ingredients.
3. In a large bowl, beat sugar and eggs until thick. Stir in oil, bananas, yogurt and vanilla. Fold in flour mix, coconut and walnuts.
4. Pour into greased 9-by 5-inch pan. Bake for 75 minutes. Let cool on rack and serve.