Lemon Zucchini Cake with a Glaze That Sets in 20 Minutes

Lemon Zucchini Cake is a 9 by 13 inch sheet cake with shredded zucchini in the batter and a lemon glaze on top, built to solve the usual glaze problem: the one that soaks into the cake and vanishes. Here the glaze goes on while the cake is barely warm, spreads to the edges, and sets in about 20 minutes. The cake serves 15, which makes it a good one for a potluck, a school event, or a week of afternoon slices. It uses 2 medium zucchini, so a bag from the supermarket, or shreds you froze earlier, works as well as anything from a garden, and it bakes in any season.

Why this works

• Glaze poured on a hot cake soaks in and disappears. Barely warm is the window where it spreads easily and still sets to a matte finish.
• Rubbing the zest into the granulated sugar for 20 seconds spreads lemon flavor through the whole batter instead of leaving it in the glaze alone.
• Squeezing the zucchini dry keeps the crumb tender instead of gummy. The shreds add moisture, and the buttermilk and oil keep the cake soft.
• Pouring the glaze over the whole top, out to the edges, means every square gets some.

What to know about the ingredients

You need 2 cups (240 g) of zucchini after shredding and squeezing. Weigh it if you can. Shred it, then wring it out in a clean kitchen towel until the drips stop. If your shreds come from the freezer, thaw them first and squeeze them the same way.

Buttermilk gives the cake a gentle tang and works with the baking soda. Fresh lemon juice matters for the glaze. The recipe uses 3 tablespoons in total, with 1 tablespoon going into the batter and the remaining 2 tablespoons into the glaze. The zest comes from 2 lemons, so zest them before you juice them, since a juiced lemon is hard to zest.

Powdered sugar makes the glaze, and you are looking for a texture that falls off the whisk in a thick ribbon. If it is too thin, it runs off the edges. If it is too thick, it will not spread.

Tips for getting it right

1. Heat the oven to 350 F (175 C) and grease the pan before you start mixing. The batter comes together quickly.
2. Rub the zest into the sugar with your fingertips until it smells like lemon and looks damp.
3. Whisk the eggs, lemon sugar, oil, buttermilk, and 15 ml (1 tablespoon) of lemon juice until smooth, about 1 minute, then stir in the shreds.
4. Fold in the dry mix only until no dry flour shows. Extra stirring makes a tougher cake.
5. Start checking at 32 minutes. The top should be pale gold, and a pick pushed into the center should come out clean.
6. Let the cake cool until it is barely warm to the touch, not hot. Pour the glaze, spread it to the edges, and leave it alone for about 20 minutes.

How to store, freeze and make ahead

Glazed cake keeps covered at room temperature for 3 days. To freeze it, cut it into squares and freeze them unglazed for 3 months. Thaw the squares, then whisk the glaze and pour it on. Glazing after thawing gives you a fresh finish instead of a glaze that has been through the freezer.

What to serve with it

This is an afternoon cake. Cut it thin, serve it with tea or a coffee, and keep the glaze side up. It also suits a brunch table beside a bowl of fruit. If you are baking for a crowd, set the Classic Zucchini Bread next to it for a plainer option, or the Fudgy Zucchini Brownies for the chocolate crowd.

Variations

• Replace part of the lemon in the glaze with another citrus juice, tasting as you go.
• Add a spoonful of poppy seeds to the dry mix for a bakery-style look.
• Skip the glaze and dust the cooled cake with powdered sugar for a lighter finish.
• Cut the cake into smaller squares for a cookie tray.

For more ways to use zucchini across the seasons, from sweet bakes to savory dinners and small-batch pantry projects, see the Zucchini Recipes and Small-Batch Preserving guide. The Zucchini Refrigerator Relish is a good savory partner to this sweet one.