MarthaStewart.com's lemon glaze and TheKitchenMagpie.com's lemon icing glaze are good recipes for lemon glaze to use on a lemon glaze cake. Lemon buttercream icing involves adding lemon juice and zest to a traditional buttercream icing recipe.
Martha Stewart's lemon glaze recipe calls for only two ingredients. Add 2 to 3 tablespoons of lemon juice to 2 cups confectioner's sugar, and stir until the mixture is thick but easy to pour. If the mixture is too thick, add more lemon juice; if it is too runny, add more sugar.
The Kitchen Magpie's lemon icing glaze recipe is slightly more complex. To make this recipe, mix 1 1/3 cups confectioner's sugar, 1/4 cup lemon juice and zest from one lemon. Combine these ingredients, then add 1 teaspoon salted butter. Microwave the glaze for 45 seconds, or until the butter is just melted, then whisk the mixture until smooth. Let this glaze sit for a few minutes before pouring over your cake or other lemon dessert.
For Wilton.com's recipe for lemon buttercream icing, cream 1/2 vegetable shortening and 1/2 cup butter. Add 2 tablespoons lemon juice and 1 teaspoon lemon zest. Gradually add 4 cups confectioner's sugar, and beat until light and fluffy. If the icing is too dry, add extra lemon juice or milk. This icing is much thicker than lemon glaze.