To make a chiffon cake, use all-purpose flour, granulated sugar, baking powder, salt, water, vegetable oil, grated lemon peel, egg yolks, egg whites and cream of tartar. Prepare a lemon glaze with butter, powdered sugar, grated lemon peel and hot lemon juice.
Adjust the oven rack to a low position and preheat the oven to 325 degrees. Mix 2 cups flour, 1 1/2 cups granulated sugar, 3 teaspoons baking powder and 1 teaspoon salt into a large bowl. Stir in 3/4 cup cold water, 1/2 cup vegetable oil, 2 teaspoons vanilla, 2 teaspoons lemon peel and 7 egg yolks. Place 1 cup egg whites and 1/2 teaspoon cream of tartar in a separate bowl and beat with an electric mixer set to high speed.
Slowly add the contents from the first bowl to the egg whites and blend with a rubber spatula until smooth. Dispense into an ungreased 10-inch tube cake pan. Bake for approximately 1 hour and 15 minutes. Remove from the oven and turn over onto a heatproof funnel. Wait 2 hours for the cake to cool and pry it from the sides of the pan with a metal spatula.
To make the glaze, simmer 1/3 cup butter in a saucepan on a low heat. Remove from the range and add 2 cups powdered sugar and 1/2 teaspoon lemon peel. Mix until even and add 2 to 4 tablespoons lemon juice one measurement at a time. When the glaze congeals, coat the cake and serve.