Preheat oven to 325°. Sift together flour, 1/2 cup sugar, and 2 tbsp. espresso powder (push through sieve). Sift again; set aside.
In a small bowl, mix remaining 1 tbsp. espresso powder with 1 tsp. hot water. Stir in vanilla and almond extracts. Set aside.
In a large bowl or standing mixer, beat egg whites until foamy. Add cream of tartar and salt. Beat until soft peaks form. Add remaining 1 cup sugar and beat until egg whites are firm but not dry. Beat in liquid espresso mixture.
Sift 1/3 of flour mixture onto egg whites and, with a rubber or silicone spatula, gently fold into whites. Add remaining flour in 2 batches, folding in gently after each addition. Turn batter into an ungreased 10-in. tube pan. Bake until browned and firm, 50 to 60 minutes.
Invert cake (in pan) on a cooling rack and let cool completely, at least 1 hour. Run a long, thin, sharp knife between cake and pan to loosen; remove cake. Keep covered, at room temperature, up to 1 day.