Fluffy Butter Streusel Loaf Cake

Oh oh. This is a first. Kinda. Because I’ve never posted a hybrid butter/yellow cake on the blog before.

I had quite the difficult time coming up with a name for this lovely loaf cake. I honestly wasn’t sure whether to call this loaf cake a butter cake or a yellow cake.

Because it’s both! This loaf is oh so fluffy and definitely isn’t as heavy or dense as your typical butter cake. But it’s also so rich in flavor that I couldn’t just relegate it to the yellow cake category. That simply wouldn’t have been fair.

What I’m saying is, this fluffy butter loaf is rich and flavorful like a butter cake yet fluffy and light like a yellow cake.

So I settled on “fluffy butter cake.”

Moving on.

Kidding, not moving on.

Here’s how this loaf cake is so rich and flavorful: its got extra egg yolks and lotsaaaa butter.

Here’s how this loaf cake is light and fluffy: it’s made with light-as-air cake flour. Sifted cake flour. And it uses a combination of sour cream and whole milk for that perfect balance of fluffiness and heftiness.

Sour cream adds a richer, but also denser, flavor and texture to cakes. Adding the milk balances that heaviness out.

Enough science.

So. This fluffy butter crumb cake is moist. And soft. And velvety. And tender. And fluffy. And also rich. And dense. And full of vanilla flavor. And has the perfect amount of sweetness.

Damn straight.

Now. Aside from its fluffy texture and super-rich flavor, this fluffy butter loaf cake also gets a streusel crumbled atop it for even more awesomeness.

A simple yet highly effective streusel made with flour and sugar (brown and white) and vanilla and butter.

When testing out this recipe, my streusel kept sinking into the batter during baking. Frustrating wasn’t even the wordddddd. What can I say, the batter was too light and delicate to handle the liberal amount of crumble I wanted scattered over it.

So, in order not to compromise on both the cake’s lightness and the streusel’s abundance, I tried a method where I sprinkled the crumble onto the cake after 15 minutes of baking time. This way, the loaf had enough time to set a bit and handle all that streusel.

And it worked!

My point is, make sure you follow the instructions and only sprinkle the streusel onto the cake after 15 minutes of baking. Otherwise, the crumble will sink into the batter.

A nice thick slice of this butter loaf cake accompanied with a steaming mug of coffee on a blistering winter day? Something to consider, in my humble opinion.

Fluffy butter streusel loaf cake - why must you be so lovely and perfect it’s not fair to the rest of us.

Fluffy Butter Streusel Loaf Cake

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Yield: 9x5” loaf/8 servings

½ cup (1 stick) butter, softened
¾ cup granulated sugar
2 teaspoons vanilla extract
1 whole egg
2 egg yolks
¾ cup plus 2 tablespoons packed cake flour (see note)
1 teaspoon baking powder
¼ teaspoon baking soda
¼ teaspoon salt
1/3 cup sour cream
2 tablespoons whole milk

 Streusel:
½ cup flour
¼ cup granulated sugar
1 tablespoon brown sugar
1 teaspoon vanilla extract
2 tablespoons melted butter

 1. Preheat oven to 350°F. Grease and line a 9x5” loaf pan.

 2. Using an electric mixer, cream the butter and sugar for a few minutes until light and fluffy. Add the vanilla extract, then the whole egg and yolks one at a time, beating between each addition. Beat till light and fluffy again.

3. Sift together the flour, baking powder, baking soda, and salt (don’t skip the sifting) and then stir to combine. In another bowl, stir together the sour cream and milk. 

4. Alternate adding the dry ingredients and sour cream mixture to the bowl of the electric mixer on low-medium speed, starting and ending with the dry ingredients. Mix till just combined.

5. Pour the batter into the prepared loaf pan, making sure the batter is even and smooth on top. Bake for 15 minutes.

6. While the loaf cake is baking, prepare the streusel: Combine all the streusel ingredients until crumbly. After 15 minutes of baking, sprinkle the streusel over cake (gently, so cake doesn’t collapse). Return the cake to the oven for about another 20 minutes, until a toothpick inserted in the center comes out clean. Don’t over bake. 

7. Let the cake cool for 10 minutes before running a knife around the edges of the cake to help release it from the pan. Invert the cake onto a cake rack and then turn right side up.

*Note: In a pinch, you can substitute all-purpose flour for the cake flour. You may also use a 9” inch round pan instead of the loaf pan; just keep in mind the cake will require less baking time in the round pan (about 18-25 minutes).