Gluten Free Lemon Poppy Seed Cake

This Gluten Free Lemon Poppy Seed Cake is one of those bakes that instantly lifts my mood. It’s soft, tender, and full of bright citrus flavor, with just the right amount of crunch from the poppy seeds. The sweet-tangy lemon glaze ties everything together beautifully, making it nearly impossible to stop at just one slice. Whether I’m enjoying it with my morning coffee or sharing it with friends over tea, this cake always feels like a little taste of sunshine.

Recipe Ingredient Notes

Gluten Free Flour: To test this Lemon Poppy Seed Snack Cake recipe, I used King Arthur Measure for Measure and Bob’s Red Mill 1-to-1. Both flour blends yielded a tender, moist crumb with exceptional flavor. I am very certain other brands will work in this recipe, I just haven’t tested them. The flour blends I used do contain xanthan gum, which helps with structure and texture.

Sour Cream: Sour Cream provides flavor in this lemon poppy seed snack cake, moisture, and fat. I use full fat sour cream for the best flavor. Substitute with Greek Yogurt if you like.

Lemons: Since this lemon cake uses a lot of lemon zest, I recommend opting for organic lemons if possible. Regardless of the type, be sure to give them a thorough rinse before using.

Poppy Seeds: You’ll find poppy seeds in the spice or baking aisle of your grocery store. Adding poppy seeds to lemon cake enhances both texture and flavor. Their subtle nuttiness and slight crunch create a delightful contrast to the cake’s soft crumb. Plus, the mild earthiness of poppy seeds balances the bright, citrusy notes of the lemon, making for a more complex and satisfying bite. It’s a classic combination for a reason!

Lemon Poppy Seed Cake

The best part about this lemon poppy seed snacking cake? No stand mixer or electric mixer is needed! The batter comes together easily in a mixing bowl with just a whisk. For baking, I recommend using an 8x8-inch square pan. If you choose a 9x9-inch pan, keep in mind that the cake will be thinner, so you’ll need to adjust the baking time accordingly.

1. Preheat the oven to 350F line an square 8" pan with parchment paper and set aside. Make sure to leave some overhang which will help to remove the lemon poppy seed cake from the pan once it has been baked.
2. In a small bowl, whisk together the gluten free flour blend (containing xanthan gum), baking powder, baking soda, poppy seeds, and kosher salt. Set aside.
3. Cut the unsalted butter into smaller pieces and place it in a microwave-safe bowl. Melt it in the microwave for about one minute. It's okay if it's not all the way melted since the carry-over heat will melt the butter all the way. Allow the butter to cool while you prepare the lemon sugar. Alternatively, melt the butter in a small saucepan over low heat on the stove.
4. In a large mixing bowl, combine the granulated sugar and lemon zest from 3 lemons. Use your fingers or the back of a spoon to rub the zest into the sugar - this releases the oils and brings out the citrus flavor.
5. Add the melted butter and vanilla extract to the lemon sugar. Whisk everything together until smooth and well combined, about 30 seconds.
6. Next, add the large eggs one at a time, whisking well after each addition until fully incorporated. I whisk each egg into the butter and sugar mixture for about 30 minutes (yes, you are getting a little arm workout with this cake).

7. Next, add the room-temperature sour cream and whisk until fully incorporated and no lumps remain.
8. Gradually add the dry ingredients to the wet ingredients, whisking to combine. Then, switch to a flexible rubber spatula and gently fold everything together until no streaks of flour remain.
9. Transfer the gluten-free lemon poppy seed cake batter to the prepared pan, using a spatula, spoon, or small offset spatula to smooth it out evenly. Gently tap the baking dish against the counter a few times to release any trapped air bubbles.
10. Place the cake in the fully preheated oven and bake for 32–35 minutes. If the center still appears underbaked, continue baking for a few more minutes until a toothpick inserted in the middle comes out clean. The top should be golden brown. Keep in mind that baking times may vary depending on your oven and the pan size used. (The recommended baking time is based on an 8-inch square pan.)
11. Remove the cake from the oven and place it on a wire rack. Let it cool in the pan for 10 minutes, then use the parchment paper overhang to lift it out. Allow the cake to cool completely on the rack before adding the lemon glaze.

Lemon Glaze

• To make the lemon glaze, whisk together sifted powdered sugar and fresh lemon juice in a small bowl until smooth. For a more intense citrus flavor, stir in a bit of finely grated lemon zest. The glaze should be thick but pourable. If you prefer a thinner consistency, add a little more lemon juice.
• Pour the lemon glaze over the cooled gluten-free lemon poppy seed cake. Use a small offset spatula or the back of a spoon to spread it evenly over the top.
• Let the glazed cake sit for 10–15 minutes before slicing and serving, allowing the glaze to set properly.

Storage & Freezing

Store any leftover gluten free lemon poppy seed cake in an airtight container at room temperature for 3-4 days. If you chose a cream cheese frosting, I recommend refrigerating it.

For best results, freeze the lemon cake before adding the glaze. Wrap the completely cooled cake tightly in plastic wrap, then in aluminum foil or a freezer-safe bag. Thaw overnight in the fridge or at room temperature before glazing and serving.

Note about Salt in my Recipes

I use Diamond Kosher Crystal Salt in all of my recipes unless otherwise stated. If use use a different brand or kind of salt in your kitchen please adjust accordingly since some salts can be saltier. If you use Morton’s Kosher Salt please be aware that their salt granules are smaller in size, denser, and crunchier and twice as salty.

Baking in grams

I share my recipes in grams and by weight since baking by weight is the most accurate way to bake. Digital Scales are very affordable and easy to use. You can purchase them on Amazon for less than a set of measuring cups. For small amounts under 10 grams, I like to use this Precision Pocket Scale. Measuring cups are very inaccurate which can cause significant errors when it comes to gluten-free baking or baking in general. Especially since I bake with gluten-free flours which weigh differently than “regular” flours. I do provide some ingredients like spices and leavening agents in measuring spoons. To learn more about Baking with a digital scale, make sure to check out my post about Baking by weight.

Note about Ovens and Oven Temperatures

All my recipes are tested and developed with a conventional oven. I always bake my baked goods on the rack placed in the MIDDLE of my oven. This way the heat coming from the bottom will not burn my baked goods.

If you are baking with convection (fan-forced), please adjust the recipes accordingly. Convection oven can cause baked goods to dry out quickly and still be raw inside. Since takes at least 15-20 minutes for a standard American Oven to be fully preheated. I highly recommend investing in an Oven Thermometer.

Substitutions and Modifications

Any dietary or ingredient modifications/substitutions to this recipe may alter the end result in appearance and taste. I test my recipes several times as published in this post and The Gluten Free Austrian Blog is not responsible for the outcome of any recipe you find on our website.