Easiest whole lemon blueberry cake

I have been intrigued by the idea of blending a whole citrus fruit into a cake ever since I first heard about the Sicilian practice of using whole oranges in cakes. I complete most kitchen tasks one-handed while holding onto a baby who likes to hang onto me like a sloth, so the idea of a cake in which I could dump everything into a blender was very appealing.

I had high hopes the first time I made a whole lemon  cake. It looked good! It smelled good! It tasted bitter. I thought that might happen because the white part underneath the skin--the pith--is indeed very bitter.

I almost gave up on the idea, but something in the back of my mind kept telling me it could work. So I tried it again and again and again. I finally developed what I think is the easiest whole lemon blender cake with lots of fresh lemon flavor and no bitterness.

The key is to use boiled Meyer lemons.

The bitterness in lemons comes mainly from compounds concentrated in the peel and pith. Meyer lemons have a thinner rind than other lemons. Additionally, boiling the lemons helps tremendously because heat breaks down the compounds that cause the bitterness.

The lemons will look like little deflated balloons when they're done boiling. Then let them cool before using them in the rest of the batter. You can do this the day before to save time.

A few more tips when making a blender cake...

Add the wet ingredients first (lemons, eggs, sugar, sour cream, and vanilla extract) and blend until smooth. Then add the dry ingredients (flour, baking powder, salt, thyme), and pulse. Just like with regular cakes, blend only until the ingredients are combined and the batter is smooth. Over mixing can result in a dense and tough cake. 

If you choose to use blueberries in the cake, toss them with a little flour before mixing them in the batter. This will prevent them from sinking to the bottom when the cake bakes.

The most accurate way to ensure your cake is done baking is to check the internal temperature. The center should be between 200 and 210 degrees Fahrenheit.

I made this recipe in a Vitamix. A food processor will also work well. If your blender or food processor is unable to hold the wet and dry ingredients, blend the wet ingredients and mix separately in a bowl with the dry ingredients.

Easiest whole lemon blueberry cake

Yield: One lemon cake

Time: About 90 minutes

Ingredients

For the cake

• 6 ounces Meyer lemons (about 3 small lemons)
• 3 large eggs
• 1 1/4 cups (250 grams) granulated sugar
• 3/4 cup (180 grams) full-fat sour cream
• 2 teaspoons vanilla extract
• 2 cups (240 grams) all purpose flour
• 2 teaspoons baking powder
• 1/2 teaspoon kosher salt
• Optional: 2 Tablespoons thyme leaves
• Optional: 6 ounces fresh blueberries mixed with 1 Tablespoon all-purpose flour

For the glaze

• 1 cup (110 grams) powdered sugar
• 3 Tablespoons fresh lemon juice

Directions

For the cake

1. Put lemons in pot with cold water and bring to boil. Boil for about 30 minutes or until lemons look deflated.
2. A few minutes before lemons are done cooking, grease loaf pan (8.5 x 4.5 x 2.75 inch) and line with parchment paper. Preheat oven to 350 degrees Fahrenheit.
3. Drain and discard cooking water. Cut lemons in quarters and discard seeds.
4. Place lemons, skins and all, in large high-powered blender or food processor.
5. Add eggs, sugar, sour cream, and vanilla to blender and blend until smooth.
6. In separate bowl, mix flour, baking powder, salt, and optional thyme. Add dry ingredients to blender and pulse until everything is just combined.
7. Toss the optional blueberries into the batter, and gently fold them in.
8. Pour batter into prepared loaf pan and smooth top.
9. Bake for about 50-55 minutes or until cake is golden and internal temperature registers around 210 degrees Fahrenheit.
10. Let cake cool for 10 minutes. Then remove it from pan and let it continue to cool on wire rack.

For the glaze

1. Once cake is cool, mix powdered sugar and lemon juice. Consistency should resemble glue.
2. Drizzle glaze over top of cake.
3. Slice cake and serve.