Preheat oven to 375 degrees with a rack set in the center of the oven.
Sift flour together with 3/4 cup sugar. Repeat process three times; set aside.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites, cream of tarter, and salt on medium speed until foamy. Add vanilla-bean seeds and almond extract. With the mixer on medium speed, slowly add remaining 3/4 cup sugar. Continue mixing until whites are glossy and stiff peaks form.
Sift enough of the flour mixture over the egg white mixture to lightly dust the top. Gently fold flour mixture into the egg white mixture. Repeat process until all the flour is incorporated into the egg white mixture.
Gently spoon batter into a 10-inch tube pan. With a spatula or knife, using a circular motion, cut through the batter twice to eliminate any large pockets of air. Smooth top to remove any large peaks.
Transfer to oven and bake until golden brown and a cake tester inserted into the center comes out clean, 35 to 40 minutes. Invert pan over a bottle (such as a 2-liter soda bottle or wine bottle) until completely cooled, about 2 hours.
To serve, set upright, and using a butter knife or a long spatula, loosen the cake from the sides of the pan. Invert onto a serving plate. Slice using a serrated knife or an angel food cake cutter; serve drizzled with bourbon creme anglaise, if desired.