1. Prepare the Oven and Pan: Position an oven rack in the lower third of the oven and preheat to 325°F (165°C). Ensure your 10-inch tube pan with removable bottom (angel food cake pan) is completely clean and dry. Do not grease the pan – the batter needs to cling to the sides to rise properly.
2. Prepare the Dry Ingredients: Sift the cake flour and 3/4 cup of the granulated sugar together onto a piece of parchment paper or into a bowl. Sift three times total to ensure it’s light and free of lumps.
3. Whip the Egg Whites: In a large, clean mixing bowl (preferably stainless steel or copper), beat the egg whites with an electric mixer on medium speed until frothy. Add the cream of tartar and salt, then continue beating until the whites form soft peaks.
4. Gradually Add Sugar: Increase the speed to medium-high and gradually add the remaining 3/4 cup sugar, about 2 tablespoons at a time, beating for a few seconds between each addition. Continue beating until the whites are glossy and form stiff peaks when the beater is lifted, but are not dry or grainy. Beat in the vanilla extract, almond extract (if using), and lemon juice.
5. Fold in Flour Mixture: Sift about one-fourth of the flour-sugar mixture over the beaten egg whites. Using a large rubber spatula, gently fold the mixture in with a cutting motion, bringing batter from the bottom of the bowl up and over the top. Repeat with the remaining flour mixture in three more additions, folding just until incorporated. Be careful not to deflate the egg whites.
6. Fill the Pan: Gently spoon the batter into the ungreased tube pan. Run a knife or spatula through the batter to remove any large air pockets. Smooth the top with the spatula.
7. Bake the Cake: Bake for 40-45 minutes, or until the top springs back when lightly touched and a toothpick inserted into the center comes out clean. The cake should be golden brown.
8. Cool Upside Down: Immediately invert the cake (in its pan) onto a bottle neck or onto the pan’s feet if it has them. Let cool completely upside down, about 1-2 hours. This step is crucial – it prevents the cake from collapsing.
9. Remove from Pan: Once completely cool, run a thin knife around the edges of the pan and around the center tube to loosen the cake. Invert onto a serving plate and gently tap to release. Use the knife to separate the cake from the bottom of the pan if needed.

Serving Suggestions:

Serve slices with fresh berries and a dollop of whipped cream. Angel food cake is also delicious with a drizzle of chocolate sauce, fruit compote, or lemon curd. For a simple presentation, dust with powdered sugar just before serving.