Lemon poppy seed cake in a 9×13 pan uses 3 cups of flour, 2 cups of sugar, 1 cup of butter, 4 eggs, 1 cup of buttermilk, the zest and juice of 3 lemons and 3 tablespoons of poppy seeds, baked at 350°F for 35 to 40 minutes. A tart lemon glaze poured over the warm cake soaks into the top and keeps it moist.
The batter is close to a pound cake, so the squares are rich and fine-grained, with a little crunch from the seeds.
Why This Recipe Fits a 9×13 Pan
Lemon poppy seed cake is usually baked in a loaf or Bundt pan, which takes an hour or more and often browns too much before the center is done. In a 9×13 the same rich batter is only about 1 1/4 inches deep, so it bakes in under 40 minutes with an even, golden top. The flat surface also takes the glaze evenly instead of letting it run down the sides.
Ingredients for a 9×13 Lemon Poppy Seed Cake
Cake
- 3 cups all-purpose flour
- 2 teaspoons baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 3 tablespoons poppy seeds
- 1 cup (2 sticks) unsalted butter, softened
- 2 cups granulated sugar
- 2 tablespoons finely grated lemon zest (from about 3 lemons)
- 4 large eggs, room temperature
- 1 teaspoon vanilla extract
- 1 cup buttermilk
- 1/4 cup fresh lemon juice
Lemon Glaze
- 1 1/2 cups powdered sugar
- 3 tablespoons fresh lemon juice
How to Make Lemon Poppy Seed Cake in a 9×13 Pan
- Heat the oven to 350°F. Grease a 9×13 pan and line the bottom with parchment.
- Whisk the dry ingredients: flour, baking powder, baking soda, salt and poppy seeds.
- Rub the zest into the sugar with your fingers until fragrant, then cream it with the butter for 3 to 4 minutes until pale and fluffy.
- Add the eggs one at a time, beating well after each, then the vanilla.
- Add the dry and wet. Combine the buttermilk and lemon juice. Mix in the flour mixture in three parts, alternating with the buttermilk mixture, on low speed just until smooth.
- Bake 35 to 40 minutes, until golden and a toothpick in the center comes out clean.
- Glaze warm. Poke the warm cake all over with a skewer, whisk the powdered sugar and lemon juice, and pour the glaze over the top.
Cook and Prep Times
- Prep: 20 minutes
- Bake: 35 to 40 minutes at 350°F
- Cool: 1 hour
- Serves: 18 to 24 squares
Changing the Pan Size
- Bundt pan (10 to 12 cup): use the full recipe and bake 55 to 65 minutes.
- Two 9×5 loaf pans: bake 50 to 60 minutes.
- 8×8 pan: halve the recipe (2 eggs) and bake 30 to 35 minutes.
Storage
Cover the cake tightly and keep it at room temperature for up to 3 days; the glaze keeps the top from drying out. Unglazed squares freeze well for up to 3 months.
Frequently Asked Questions
Why did my cake turn out dense?
The butter and eggs were probably cold, or the batter was overmixed after the flour went in. Room-temperature ingredients cream into a lighter batter.
Can I use bottled lemon juice?
Use fresh lemons for the zest at least; that is where most of the lemon flavor lives. Bottled juice works in the glaze.
Can I make it without poppy seeds?
Yes. Leave them out and you have a plain lemon sheet cake.
For more bakes sized for the same pan, see our lemon cake for a 9×13 pan, lemon lush in a 9×13 pan and lemon cheesecake bars in a 9×13 pan.