- With the rack in the middle position, preheat the oven to 350°F (180°C).
- In a bowl, combine the flour, baking powder and salt. Set aside.
- Place the egg whites in a large bowl. Set aside.
- In a large pot, bring the maple syrup to a boil. Let cook on high without stirring until a thermometer reads 250°F (120°C), about 10 minutes.
- With an electric mixer on medium speed, beat the egg whites until soft peaks form. With the mixer running, drizzle the hot syrup over the egg whites, avoiding the beaters. Increase the speed and continue to beat until the meringue forms stiff peaks.
- In a large bowl, whisk the egg yolks together with the cream and vanilla. Add the dry ingredients and whisk until smooth. Fold 1/4 of the meringue into the batter. Still using a whisk, gently fold in the remaining meringue.
- Pour the batter into an ungreased non-stick 10-inch (25 cm) angel food cake pan. Bake for 50 minutes or until the surface of the cake springs back when pressed.
- Remove from the oven and immediately turn the cake pan upside down onto a wire rack. Let cool completely, about 3 hours. Run a thin blade between the cake and the pan before unmoulding. The cake will keep, covered, for 3 days at room temperature. When ready to serve, drizzle with maple butter.
Because the only fat in this recipe comes from 35% cream, it’s advisable not to replace it with a lighter variety.