Step 1Sift together flour and 3/4 cup sugar. Add egg yolks, water, lemon juice and 1 teaspoon vanilla. Beat on medium speed until mixture is smooth and thick, 2 minutes.
Step 2In a large bowl, beat egg whites, remaining 1/2 teaspoon vanilla, cream of tartar and salt until mixture has formed peaks that roll over at the tops when beaters are lifted. Gradually add remaining 3/4 cup sugar, 2 tablespoons at a time, until meringue is firm and forms stiff peaks. Gently pour flour-egg mixture over meringue, and fold in with slotted spoon or rubber spatula. Gently scoop batter into ungreased 10-inch tube pan. Cut through batter with a knife 5 or 6 times to remove air bubbles.
Step 3Bake at 350 degrees until cake springs back when touched, 40 to 45 minutes. Invert and cool.
Step 4Remove from pan and cut into 4 layers. Spread Coffee Crunch Icing generously between layers and over top and sides of cake. Store cake in refrigerator until ready to serve.
Step 1Combine 1 1/2 cups sugar, coffee and syrup in saucepan and bring to boil over low heat. Cook until syrup registers 300 degrees on candy thermometer or reaches the hard-crack stage. Remove from heat and immediately add baking soda. Stir until mixture thickens and pulls away from sides of pan. (Mixture forms rapidly when soda is added.) Pour into greased shallow pan. Do not spread or stir. Let stand without moving until cool, 1 hour. When ready to garnish cake, knock candy out of pan and crush between 2 sheets of wax paper.
Step 2Whip cream until foamy, gradually adding reserved sugar and vanilla. Beat on high speed until stiff, 3 to 4 minutes.
Step 3Fold crushed crunch candy into whipped topping. Spread generously between layers and over the top and sides of the cake. Store cake in the refrigerator until ready to serve.