RUBY RED GRAPEFRUIT CAKE

2 c. cake flour

1½ c. granulated sugar, divided 

2 tsp. baking powder 

½ tsp. salt 

6 eggs, separated 

2/3 c. canola oil 

2/3 c. plus 1 Tbs. fresh grapefruit juice, divided 

2 tsp. lemon zest 

2 tsp. vanilla 

1 tsp. cream of tartar 

1½ c. powdered sugar 

1 tsp.-fresh mint, minced

Preheat the oven to 350°F. Butter and flour a 10-inch bundt pan. Set aside. In a large bowl, sift together flour, 1 c. granulated sugar, baking powder and salt. Set aside. In a small bowl, mix together egg yolks, oil, 2/3 c. grapefruit juice, lemon zest and vanilla. Mix this mixture into the flour mixture until smooth. In yet another large bowl, beat the egg whites with the cream of tartar until soft peaks form. Gradually add the remaining ½ c. sugar one tablespoon at a time and beat until stiff peaks form. Gently fold the egg whites into the cake batter and spoon it into the prepared cake pa...