Soft Buttermilk Coffee Cake with Cinnamon Streusel
This buttermilk coffee cake has a soft, tender crumb and a thick, buttery cinnamon streusel that stays crunchy on top. It’s the kind of cake that makes a weekday morning feel like a slow Saturday.
A generous pour of tangy buttermilk keeps it moist without weighing it down, and the ribbon of cinnamon sugar through the middle gives you pockets of sweetness in every bite. No mixer needed, just two bowls and a whisk.
Why This Coffee Cake Turns Out So Tender
Buttermilk does more than add flavor here. Its acidity reacts with the baking soda, creating a fine, even crumb that stays soft for days. This is the cake I reach for when I want something reliable and uncomplicated.
The streusel uses melted butter, which helps it form crisp, clumpy crumbles instead of sandy dust. A little extra cinnamon in the center swirl means every forkful has a hit of warm spice.
Ingredients
- 2 cups all-purpose flour: spooned and leveled, not scooped
- 1 tsp baking powder: helps the cake rise tall
- ½ tsp baking soda: reacts with the buttermilk for tenderness
- ½ tsp fine sea salt: balances the sweetness
- ½ cup unsalted butter, softened: gives the cake a rich crumb
- ¾ cup granulated sugar: sweetens without making it heavy
- 2 large eggs, at room temperature: binds the batter and adds structure
- 1 tsp vanilla extract: rounds out the buttermilk tang
- 1 cup buttermilk, well shaken: the key to a moist, tangy crumb
- For the streak: ¾ cup all-purpose flour, ½ cup packed light brown sugar, 2 tsp ground cinnamon, 5 tbsp unsalted butter melted
- For the swirl: 2 tbsp granulated sugar mixed with 1 tsp ground cinnamon
Variations and Substitutions
- No buttermilk?: Stir 1 tbsp lemon juice or white vinegar into 1 cup whole milk and let it sit for 5 minutes.
- Dairy-free: Use a thick plant yogurt mixed with a splash of water to mimic buttermilk, and swap the butter in the cake for a neutral oil.
- Add nuts: Fold ½ cup chopped toasted pecans or walnuts into the streusel for extra crunch.
- Fruit swirl: Toss 1 cup fresh or frozen blueberries with the cinnamon sugar before swirling in, no need to thaw.
If you love a morning cake, our Sour Cream Blueberry Loaf is a great one to bake next.
How to Make Buttermilk Coffee Cake
Step 1: Make the Cinnamon Streusel
In a small bowl, stir together the ¾ cup flour, ½ cup brown sugar, and 2 tsp cinnamon until no lumps remain. Pour the 5 tbsp melted butter over the top and mix with a fork until the mixture looks like damp, clumpy sand. Set the bowl aside.
You want pea sized lumps and a few larger ones. Those bigger pieces will bake into crisp little nuggets on top.
Step 2: Mix the Cake Batter
Whisk the 2 cups flour, 1 tsp baking powder, ½ tsp baking soda, and ½ tsp salt together in a medium bowl. In a large bowl, beat the ½ cup softened butter with the ¾ cup granulated sugar using a whisk or a spatula until it looks pale and fluffy, about 2 minutes. Add the 2 eggs one at a time, beating well after each, then stir in the 1 tsp vanilla.
The butter mixture should look creamy and lightened in color, not separated. If it curdles a little after adding the cold eggs, just keep mixing until it smooths out again.
Step 3: Alternate Wet and Dry Ingredients
Add the flour mixture to the butter mixture in three parts, alternating with the 1 cup buttermilk, starting and ending with the flour. Stir just until no dry streaks remain after each addition. Scrape the sides of the bowl once halfway through.
The batter will be thick and slightly lumpy, which is exactly what you want. Overmixing here tears through the gluten and gives you a tough cake.
Step 4: Layer and Swirl the Batter
Preheat your oven to 350°F (175°C) and butter an 8 inch square baking pan. Spread half the batter evenly into the pan. Sprinkle the cinnamon sugar mixture for the swirl over the top, leaving a ½ inch border. Spoon the remaining batter over the sugar in dollops, then use an offset spatula to gently spread it to the edges. Top with the streusel in an even layer.
Don’t worry if a little batter pushes through the streusel. It all bakes together into a golden, bumpy top.
Step 5: Bake and Cool
Bake the cake on the center rack for 42 to 47 minutes, until the top is deeply golden and a toothpick inserted into the center comes out with a few moist crumbs clinging to it. Let the cake cool in the pan on a wire rack for 20 minutes.
The cake needs that cooling time to set its crumb fully. Slice it into squares and serve warm or at room temperature. The inside should be soft and the top will crackle slightly when you cut into it.
Tips for the Fluffiest Coffee Cake
- Room temperature ingredients prevent a dense crumb.: Set the eggs and buttermilk on the counter 30 minutes before you start, or place the eggs in warm water for 5 minutes.
- Don’t over-swirl in Step 4.: A light spread keeps the cinnamon ribbon distinct instead of muddying into the batter.
- Check early if using a glass or dark metal pan.: These pans absorb heat faster, so start testing at 38 minutes.
- For the tallest rise, bake right after assembling.: Leaving the batter sitting too long wastes the first kick from the baking powder and soda.
Bake times by pan:
| Pan Size | Material | Bake Time |
|---|---|---|
| 8×8 inch square | Light metal | 42-47 mins |
| 9 inch round | Light metal | 38-42 mins |
| 9×5 inch loaf | Light metal | 50-55 mins |
Storing Leftover Coffee Cake
- Refrigerate: Keep slices in an airtight container at room temperature for up to 3 days, or in the fridge for 5 days. The cake stays moist either way.
- Reheat: Warm a slice in a 300°F oven for 5 to 7 minutes to re-crisp the streusel. A microwave works in a pinch, but the topping will soften.
What Goes Well With This Coffee Cake
A strong, black coffee cuts through the sweetness and lets the cinnamon come through. For a brunch spread, pile a bowl of fresh berries next to the cake and a simple herby frittata on the side. The fruit brightens every bite, while the eggs turn a slice of cake into a full plate.
Frequently Asked Questions
Can I use milk instead of buttermilk?
Yes, but you need to acidify it. Stir 1 tablespoon of lemon juice or vinegar into 1 cup of whole milk and let it sit for 5 minutes before using.
How can I tell when the cake is done without a toothpick?
The top should spring back when you press it lightly with a fingertip, and the edges will have pulled away from the sides of the pan just a bit.
Can I freeze this coffee cake?
Yes. Wrap the completely cooled cake, whole or in slices, tightly in plastic wrap then foil. Freeze for up to 2 months. Thaw at room temperature and reheat to refresh the top.
My streusel sank into the batter. What went wrong?
The batter was likely too thin or over stirred, or the streusel was added too early and the batter rose up around it. Make sure the top batter layer is thick enough to hold the weight.
Buttermilk Coffee Cake Recipe
Ingredients
Method
- Stir together the streusel dry ingredients, then mix in the melted butter until clumpy. Set aside.
- Cream the softened butter with sugar, then beat in eggs and vanilla until fluffy.
- Whisk together the flour, baking powder, baking soda, and salt. Add to the butter mixture alternately with the buttermilk, starting and ending with flour, stirring just until combined.
- Spread half the batter into a buttered 8 inch square pan. Sprinkle the swirl sugar mixture over it, then top with the rest of the batter and spread even. Cover with streusel.
- Bake at 350°F (175°C) for 42 to 47 minutes, until a toothpick comes out with moist crumbs. Cool in the pan for 20 minutes before slicing.
