Beat egg whites (at room temperature) until foamy; add cream of tartar and salt; beat until soft peaks form. Gradually add sugar, 2 tablespoons at a time, beating mixture until stiff peaks form
Sprinkle flour over egg white mixture; fold in carefully. Gently fold in flavorings.
Pour batter into an ungreased 9-inch square baking pan; sprinkle coconut over top. Bake at 325° for 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pan about 40 minutes. Remove cake from pan, and cut into squares to serve.