Preheat oven to 300 degrees F. Coat a 9-inch springform pan or 8-inch square cake pan with cooking spray.Advertisement
Stir together flour, sugar, cinnamon, baking powder and salt in a mixing bowl with a fork. Add oil, egg whites, butter and 1 teaspoon vanilla; mix with a fork or your fingertips until well blended. Press into the bottom of the prepared pan.
Whisk together egg, condensed milk and cornstarch in a mixing bowl until smooth. Add yogurt and whisk until smooth. Blend in lemon zest and the remaining 1 teaspoon vanilla. Pour over the crust. Sprinkle blueberries evenly over the top. Bake the torte until the top is just set, 1 1/4 to 1 1/2 hours. (The center will quiver slightly when the pan is gently shaken.) Let cool in the pan on a rack. Loosen edges and remove the pan's outer ring. Serve warm or chilled, dusted with confectioners' sugar.
2 1/2 other carbohydrate, 1 fat