Strawberry swirl yogurt cake

Do you ever wake up in the morning and decide that you’re going to do things the hard way? 

Because apparently I do. 

Last week the grocery store had decent-looking strawberries, and I was seized with the urge to make a strawberry cake. And not just any strawberry cake, but the strawberry cake I use for weddings – plush, finely textured, and rich with butter and egg yolks, filled with a strawberry-balsamic-black pepper jam. But I wanted it now, and I didn’t want to deal with my stand mixer, or with stacking, filling, and frosting a layer cake. 

I also didn’t want to spend time finding a recipe that checked all those boxes. 

So I decided to do it myself – partly because I’m apparently a masochist, and partly because the science of baking is just really freaking interesting. 

Coming up with a cake from scratch seems scary, but, as with most baked goods, successful recipes are based on simple ratios and rules. Batters need balance – flour, dairy, and eggs for strength, fat and sugar for tenderness. 

Cake Ratios

In general, butter or oil-based follow one of two patterns – lean cakes, which have less sugar than flour, and high-ratio cakes, which have more. If you’ve baked a pound cake, butter cake, or classic yellow birthday cake from scratch at home, odds are that it was a lean cake, and it followed these three rules: 

1. The weight of the sugar should be equal to or less than the weight of the flour
2. The weight of the eggs should be equal to or greater than the weight of the fat
3. The weight of the liquids (eggs and milk or their equivalents) should equal the weight of the flour. 

In general, I prefer high-ratio cakes. I find them richer and more tender than lean cakes, with better shelf life and crumb. To prove my point – almost all chocolate cake recipes are high ratio. To deal with the extra sugar and keep the batter balanced, the rules for these cakes are a little different: 

1. The weight of the sugar should be equal to or greater than the weight of the flour
2. The weight of the eggs should be greater than the weight of the fat
3. The weight of the liquid (eggs and milk or their equivalents) should be equal to or greater than the weight of the sugar. 

According to Shirley O. Corriher (a food scientist and all-around wonderful resource – I reach for her books constantly), you have some wiggle room – but you need to be within 20 percent of the ideal or your recipe won’t work. 

Ratio to Recipe

How do you use these rules to get a recipe? Well, first you have to decide what ingredients you’re using, and after that, it’s just math. 

The fat and dairy you choose for your cake can make a big difference in the final texture. I wanted a plush, moist crumb with a little bit of tang, and I wanted it to come together quickly, by hand, and with the minimum number of dishes. 

The first thing I picked was my fat. Creaming butter by hand is a nightmare – I went with oil to save my poor arms. I knew the strawberry flavor would mask any nuance in olive oil, so canola was my pick. 

As for dairy, I wanted the tang from the buttermilk in my wedding cake recipe, but I almost never have it on hand. I could use yogurt or sour cream for a similar taste, and between the two I’m more likely to have yogurt in the house. So yogurt it was. 

I’m not going to put you through the 30 minutes of painful mathematics that got me to the final recipe (I don’t want to relive it), but suffice it to say that I followed the formula then fussed with leavening and flavors until I got something that looked like a cake recipe. 

Testing, Testing, 1 2 3…

At this point, I had a recipe to work from, but I knew that my leavening was more or less a blind guess, and was more than halfway convinced that I was going to pull a sweet brick out of the oven after the first round of testing. 

Only one way to find out. 

I threw together a batch of strawberry balsamic jam and made my cake. It didn’t look promising in the pan – the strawberry balsamic jam had turned half the batter into soup, and the black pepper specks looked and smelled very aggressive. But when I pulled it out, it looked like cake! 

And when I cut into it, it had the texture and richness I was looking for, with balanced sweetness and a nice crumb. Sure, the strawberry swirls were gummy and the black pepper was overwhelming, but those things felt easily fixed. 

So I tried again – I figured that the homemade jam was too wet, so I tried slow-roasting the strawberries to pull out moisture. I also decided to try storebought jam mixed with a little balsamic vinegar, thinking that it might be thicker than my homemade stuff, and therefore less likely to mess with the texture. 

Of the two, the cake with roasted strawberries was the clear winner. The cake with the jam didn’t have textural problems, but its flavor was anemic, and the swirls were so pale that it was barely worth bothering. By contrast, the cake with the roasted strawberries was bright and fruity, with a beautiful purple-red swirl that held up well through baking. Was it the punchy in-your-face strawberry of my wedding cake? Not exactly. But it was enough to satisfy my craving – and the softer, subtler strawberry is perfect for snacks.

Of course, now I have three cakes taking up space on my kitchen counter.

I’ve had worse problems.

Further Reading

• Corriher, Shirley O. CookWise: No More Failed Recipes: the Hows and Whys of Cooking. William Morrow, 1997. Pages 135-153
• “For Cakes, Get the Ratios Right.” Fine Cooking
• “Cake Batter Salt & Leaveners.” Baking Sense: The Art and Science of Baking

Strawberry Swirl Yogurt Cake

Yield: 1 loaf     Time: 1.5 hours    Source: The Eighth Street Mess, based on the high-ratio cake rules by Shirley O. Corriher

• 233 grams (1 cup + 2 tablespoons) granulated sugar
• 2 large eggs
• 116 grams (scant 1/2 cup) plain full-fat Greek yogurt
• 7 grams (1 teaspoon) vanilla extract
• 215 grams (1 1/2 cups) all-purpose flour
• 5 grams (3/4 teaspoon) baking powder
• 1 gram (1/4 teaspoon) baking soda
• 1/2 teaspoon salt
• 106 grams (1/2 cup) vegetable oil, such as canola
• 1/4 teaspoon black pepper, ground fine
• 1 recipe slow-roasted balsamic strawberries, pureed
• Preheat oven to 350°F(176°C).

In a large bowl, whisk together the eggs and sugar until they have lightened to a very pale yellow color and forms a ribbon as it falls off the whisk. Add the yogurt and vanilla, and whisk until no lumps of yogurt remain. 

Combine the flour, baking powder, baking soda, and salt (you can do this in a separate bowl, but I just dump everything in the sifter and go from there), and sift over the egg mixture. Depending on your salt and how fine your mesh is, you may have salt left in the sifter – this is fine, just dump it into the bowl. The important thing is that you don’t have lumps of flour or baking powder. 

Fold the flour into the egg mixture with a rubber spatula. I find the fastest way to do this is to rotate the bowl as you fold, but however you choose to work will be fine. Just keep going until no streaks of dry flour remain. Add the oil and keep folding until it is fully incorporated. Keep an eye on the sides of the bowl – oil likes to puddle on the edges. 

Divide the batter evenly between two bowls. Fold the pepper into one bowl and the strawberry puree into the other, making sure everything is thoroughly incorporated. 

Grease an 8.5”x4.5”x2.75” loaf pan with non-stick cooking spray, and line with parchment if you like. If you don’t go the parchment route, you want to grease the pan VERY well – this cake is on the stickier side. 

Dollop the batter into the pan, alternating between the strawberry and black pepper. Once you’ve got it all in the pan, swirl through it with something long and relatively thin – a butter knife, cake tester, or bamboo skewer would all work well. 

Bake until a toothpick inserted into the center of the cake comes out clean, 45-55 minutes. 

Slow-Roasted Balsamic Strawberries

Yield: about half a cup Time: 1.5-2 hours Source: The Eighth Street Mess

• 406 grams (3 cups) sliced strawberries (I find this is equivalent to a one-pound package, minus a few for snacking) 
• 64 grams (1/4 cup + 1 tablespoon) granulated sugar
• 9 grams (2 teaspoons) balsamic vinegar
• Pinch salt 
• Preheat oven to 275°F(135°C).

Toss the strawberries with the sugar, balsamic, and salt. Allow the strawberries to sit for at least 30 minutes, stirring occasionally, then dump the whole mixture, juice and all, onto a parchment-lined baking sheet (DO NOT use a flat cookie sheet for this – you want one with sides or you’re going to have a bad time). 

Let the strawberries roast until the juice on the tray thickens and the strawberries look dry on top. If you turn the tray sideways, the juice should no longer run. For me, this took about an hour and a half, but it will depend on your oven and how juicy your strawberries are. I’d start checking them an hour in. 

Remove from the oven and let cool. Scrape the strawberries and juice off the pan as best you can, and store in an airtight container until you’re ready to use.