High Altitude Lemon Poppy Seed Crumb Cake

A high altitude lemon crumb cake, flecked with poppy seeds, swirled with lemon curd, and sprinkled with buttery crumble topping. This moist lemon poppy seed cake is delicious served warm for breakfast, like a lemon coffee cake.

You might also love this no churn lemon poppy seed ice cream, soft and chewy lemon poppy seed cookies, and high altitude lemon poppy seed layer cake.

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Why You’ll Love This Recipe

Moist and Soft. With plenty of sour cream, whole milk and butter in the cake, it stays soft and moist and days after baking.

Enjoy Warm from the Oven. I love a cake recipe that doesn’t need to cool for long before you can cut into it. And a crumbly, lemon poppy seed breakfast cake is the perfect sort of cake to enjoy while it’s still warm.

High Altitude Tested. I develop all the recipes on my site for Denver’s altitude of 5,280 feet. If you’re at a lower or higher elevation, please see my FAQs for guidance on adjusting recipes for your altitude.

See the recipe card at the end of the post for the full ingredients list and instructions.

Ingredients

• Granulated Sugar. Adds sweetness, and moisture. By rubbing the lemon zest into the sugar for the crumb topping and cake batter, you’ll be adding even more delicious lemon flavor to the cake.
• Lemon Zest. You’ll need to zest a fresh lemon. Dried lemon peel will not give you the same flavor.
• Flour. I used all purpose flour for the crumb topping and cake flour for the cake batter. The flour gives the cake its structure and strength.
• Salt. Balances the sweetness.
• Butter. Unsalted butter moistens and binds together the crumb topping and adds moisture and flavor to the cake.
• Egg. Adds moisture and strength to the cake.
• Sour Cream + Whole Milk. Adds moisture, fat and flavor.
• Vanilla + Lemon Extracts. Flavor.
• Baking Powder. Leavening agent, so the cake rises as it bakes.
• Poppy Seeds. Adds a nutty crunch and pretty speckled appearance.
• Lemon Curd. You can use store bought or homemade lemon curd. Swirled into the cake batter, it bakes into the cake, adding moisture and even more lemon flavor.

Instructions

Getting Ready

• Preheat the oven to 350 F, and position a rack in the center of the oven.
• Lightly spray an 8 or 9 inch square baking pan with non-stick baking spray, or line with parchment paper.

Crumb Topping

• In a bowl, rub together the sugar and lemon zest until moist and fragrant. Add the flour and salt.
• Stir in the melted butter until moist and crumbly, then set aside until needed.

Cake Batter

• In a bowl, rub together the sugar and lemon zest until moist and fragrant. Whisk in the egg, sour cream, milk, vanilla extract, lemon extract and melted butter.
• Separately, sift together the flour, baking powder, salt and poppy seeds. Add the dry ingredients to the wet, and stir just until moistened.

Bake

• Spread the cake batter into the prepared pan, dollop with the lemon curd, and gently swirl it in with a knife. Sprinkle with the crumb topping.

• Bake the cake for about 40-45 minutes for a 9 inch pan or 50-55 minutes for an 8 inch pan, until a cake tester or sharp knife inserted in the center comes out clean.
• Let the cake cool for 1-2 hours before cutting. Enjoy the cake warm or at room temperature.

Be sure to read all of my BAKING FAQs where I discuss ingredients, substitutions and common baking questions, so that you can be successful in your own baking!

Frequently Asked Questions

How long does this lemon crumb cake stay moist?

Stored in an airtight container, your lemon poppy seed crumb cake will stay moist for up to 3 days.

What’s the best way to reheat leftover cake?

Warm up leftover pieces of cake in the microwave for 30-45 seconds at 50% power for a soft, just-baked texture.

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