When life gives you lemons, make this moist, tangy cake.
When I was a little girl, I loved lemons. I’d eat them by themselves, in hot tea, in iced tea, and in pie. I couldn’t wait until summertime to wow the neighbor kids with my ability to not make a sour face when I sucked on a fat wedge.
Every summer, I went to my grandmother’s house. She made a delicious lemon cake that was topped with a super sour lemon glaze. I always asked for the edge pieces because they were the lemony-est.
Now, when I eat her lemon Jell-O® cake, I’m transported to the Fourth-of-July in her back yard. My uncle, cousin and I would hold a sparkler in one hand and a piece of cake in the other. Firecrackers banged and popped all over the neighborhood and tangy lemon exploded in our mouths.
When I was 34, my mother passed away, and I realized that I didn’t have her mother’s cake recipe. Luckily, before my dad passed in 2020, he handed me a box of recipes that my mother collected over the years. The lemon Jell-O® cake was in it. It felt like Christmas came in January all over again.
Since the pandemic, I have become obsessed with making sourdough and adapting recipes to use up the discard instead of wasting it. With a few tweaks to my grandmother’s recipe, this beloved family favorite is even better.
Lemon Jell-O® Sourdough Cake Ingredients
1 boxed super moist lemon cake mix
1 3-oz. box of lemon Jell-O® gelatin
Lemon zest, finely grated (from 3 large lemons, reserve 1 tsp. for glaze)
¾ c. Oil (any neutral flavor such as Canola, corn, or all-vegetable oil)
3 eggs (beaten)
1 c. (225 g.) sourdough starter discard
½ c. (4 oz.) freshly squeezed lemon juice (2 large lemons)
1 tsp. butter flavoring (optional)
1 tsp. lemon extract
Instructions for the Lemon Jell-O® Sourdough Cake
Preheat your oven to 325℉. Adjust your oven rack to the middle position in your oven. Spray a 9-inch x 13-inch cake pan with oil, or grease it with shortening and dust it with flour.
In a large bowl, whisk together the cake mix, Jell-O® and lemon zest. In a large measuring cup, beat together the eggs and oil until well combined. Stir in the lemon juice, butter flavoring and lemon extract. Finally, mix in the sourdough discard until fully incorporated.
Fold the wet mixture into your dry ingredients and mix until no dry pockets remain. If you prefer, you can put your dry ingredients into your stand mixer bowl and add the wet ingredients gradually while mixing. You may also use a hand mixer, but I find a whisk works just as well.
Pour your batter into your 9 x 13-inch prepared cake pan and smooth it out evenly. Place the pan on the middle rack of your preheated oven and bake for 20 minutes. Rotate the pan 180-degrees to promote even browning. Continue to bake 20 more minutes.
A toothpick inserted in the middle of the cake should come out clean, with no raw dough clinging to it. Remove the pan from the oven and place it on a wire cooling rack.
Make the lemon glaze while the cake bakes.
1 c. (120 g.) powdered sugar
½ c. lemon juice
½ tsp. lemon zest
While the cake is baking, combine all the ingredients in a measuring cup and whisk thoroughly. The glaze will be thin and pour easily over the cake. While the cake is still piping hot, poke random holes all over the cake with a toothpick or meat fork. Drizzle the glaze over the entire surface of the cake before it cools.
To store left-overs, if there are any, tightly cover the pan with plastic wrap. There is no need to refrigerate it. If, however, you make it for yourself and no one else, cut the cake into serving-sized pieces and place them into a freezer bag. This cake freezes well and will be good for at least a month.
Why this Lemon Jell-O® Sourdough Cake Recipe works.
The sourdough discard enhances the tangy flavor of the lemons and adds a moist, springy texture to the batter. The glaze soaks into the crust of the cake, making the edges extra sour. Also, using the lemon cake mix makes this a super easy recipe.
Lemon zest is the finely grated yellow part of the lemon rind. It has concentrated lemon flavor that easily permeates entire dishes, even in small amounts. The use of lemon zest in this recipe boosts its sourness. And you use a bunch of it.
You want to grate only the yellow portion of the skin without the white part of the rind underneath it. The white part is bitter and will give the cake a chemical taste. Using a microplane grater like this one or this one makes the job easy. (Not affiliate links.)
A new legacy recipe for future generations.
This cake turned out so moistly delicious I began to imagine other versions. I would love to try making an Orange Dream Cake using orange Jell-O®, orange juice, orange zest, and orange extract.
I think it would be possible to use any fruit flavored Jell-O® and freshly squeezed juice. You’re only limited by your imagination.
My sourdough version of Grandmother’s legacy recipe is sure to become your family favorite, too. And you won’t waste sourdough discard either.