Buttermilk Sheet Cake With Peaches and Blueberries; get the recipe, below. (Stacy Zarin Goldberg for The Washington Post; food styling by Lisa Cherkasky for The Washington Post)

A few years ago, I was e-gifted a recipe for a simple fruit-topped cake called Cup o’ Cup o’ Cup o’. The email ended with “I bet my mother made 1000 of these when we were kids.” The straight-up recipe starts with melting a stick of butter in the oven in the cake pan (easier to grease the pan), then pouring the liquid butter into a bowl with a cup of flour, a cup of milk and a cup of sugar, plus a good amount of baking powder. Once these ingredients are stirred together and scraped into the pan, a riot of summer fruit is dumped on top and the cake bakes into either a puddinglike form, warm and gooey, or a firmer cake with well-browned edges, entirely dependent on the amount of time it spends in the oven.

I made the cake a few times and liked it well enough. It was close, but not the treat I thought it could be. I was less fond of the pudding form and more entranced with those crispy edges. I set to work and made this cake my own, one intended for the potluck table. In the past month, I doled out this cake to friends, family members, workmen and soon-to-be-neighbors, making a dozen versions until it reached, in my mind, its full potential.

From the outset, I knew I wanted this to be a buttermilk cake. Buttermilk from my local dairy is thick and creamy and glugs out of the bottle. For this cake, the buttermilk from the grocery store works as well, but the thicker version makes a cake with a slightly more moist and tender crumb.

Changing from whole milk to buttermilk in the original cake meant adjusting the leavener from baking powder to baking soda (unlike milk, buttermilk does not need cream of tartar, an acidic ingredient in baking powder, to activate the leavening), and I fiddled with the amount of, well, everything else. I added eggs. I upped the flour. I changed the ratio of fruit to batter. And I changed the pan size. The result is a cake that is somewhat muffin-like, a little like a coffee cake, and reminiscent of pound cake.

I used whatever fruit was on hand to top the cake. I combined berries. I used white and yellow peaches. I stirred together sweet and sour cherries. Any fruit fits the bill and scents the cake while it bakes.

This is a cake that any baker will want to make their own. I know because I gave the recipe to two friends and they both changed it up. I use vanilla to further scent the cake, but my friend Gail used almond extract. When I added cinnamon, I thought it overwhelmed the flavor of the fruit and the tang of the buttermilk, but Abbie added nutmeg and was happy. I think cardamom might be delicious, too.

Here is your new go-to summer cake. Make it once, and I suspect you’ll make it again and again, as I have. Slice the cake into big square slabs; no one will complain if their piece has a scoop of ice cream snuggling up next to it. Around here, we’ve been calling it breakfast cake with absolutely no guilt. And if there is buttermilk left over, it makes delicious biscuits, is a first-rate brine for chicken, and is a good sipping drink on a hot day, or so said my grandfather.

Barrow is a Washington cookbook author. She’ll join Wednesday’s Free Range chat at noon: live.washingtonpost.com.

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If you don’t have a stand mixer, a hand mixer and a large bowl will work just as well.

MAKE AHEAD: Cover the cake tightly and store it on the counter for about 3 days.

From Bring It! columnist Cathy Barrow.

Ingredients

16 tablespoons (226 grams; 2 sticks) unsalted butter, at room temperature, plus more for the pan

3 cups (360 grams) flour

½ teaspoon (3 grams) baking soda

½ teaspoon (3 grams) kosher salt or fine sea salt

2 cups (400 grams) sugar

3 large eggs, at room temperature

½ teaspoon vanilla extract

1 cup well shaken buttermilk, preferably full-fat

3 peeled, pitted peaches, sliced ½ -inch thick (about 2 cups; can use frozen; see NOTE)

1 cup (150 grams) fresh or frozen blueberries

Steps

Preheat the oven to 350 degrees. Line a 9-by-13-inch baking pan with parchment paper so the two shorter sides overhang a bit (for lifting the cake out of the pan.) Grease the paper with a little butter.

Whisk together the flour, baking soda and salt in a medium mixing bowl.

Combine the 16 tablespoons of butter and the sugar in the bowl of a stand mixer; beat on medium speed, 3 to 4 minutes, until light and fluffy. Add the eggs one at a time, mixing well after each addition. Scrape down the bowl from time to time.

Add the vanilla extract to the buttermilk and stir to combine. On low speed, alternately add the flour mixture and the buttermilk mixture in two or three additions, ending with the flour, mixing until just barely incorporated. Use a flexible spatula to gently fold the batter a bit more by hand, making sure to scrape the bottom of the bowl to work in any residual dry ingredients. Once the batter looks combined with no white streaks, scrape it into the prepared pan. Smooth the top with an offset spatula.

Arrange peach slices on the top and scatter the blueberries evenly over the peaches. Bake (middle rack) for about 1 hour (start checking after 50 to 55 minutes), until the cake is golden brown on the edges and begins to pull away from the sides. During the baking, the batter will puff up over the fruit; once the cake cools, it will deflate a bit.

Transfer to a wire rack to cool completely (in the pan). Lift the cake using the parchment paper ends, then discard the paper and cut into 15 to 20 squares.

NOTE: To peel peaches, plunge them it into boiling water for 30 to 45 seconds, then use a slotted spoon to transfer them to a bowl of ice water. As soon as they are cool enough to handle, slip off the skins. The riper the peach, the less time it needs in the boiling water.

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