21/4 tsp. baking powder

1/2 tsp. salt

3 T. butter

3 T. canola oil

1 C. sugar

4 egg whites

2/3 C. buttermilk

1 T. fresh lime juice

11/2 tsp. grated lime zest

1 tsp. vanilla extract

 

Preheat the oven to 350°F. Lightly spray a standard-size (9 x 5-inch) loaf pan with non-stick cooking spray. Combine the flour, baking powder, and salt in a medium bowl and set aside. In another bowl combine the butter, oil, and sugar and mix until smooth. Add the egg whites and beat with an electric mixer until the batter is smooth. Alternately add the flour and buttermilk to the egg mixture, ending with flour. Add the lime juice, grated lime zest, and vanilla and mix until smooth. Pour into the prepared loaf pan. Bake in the preheated oven for 35 to 45 minutes, or until the top is golden brown. Remove from the oven and cool in the pan on a rack for at least 10 minutes before slicing.