it's that time of year when summer edges up against fall. the weather is changeable, shifting from sunny and warm to grey and rainy over the course of a few hours. summer fruit is still abundant but the cooler days call out for a comforting treat. that's where this coffee cake comes in. the classic vanilla-scented batter is lightened with greek yogurt, rather than the traditional sour cream, and while I added italian plums, you could easily substitute blueberries or peaches, or whatever fresh fruit you fancy. the simple crumb topping adds a lovely finishing crunch.

ingredients

for cake
2 1/2 cups all purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1/4 teaspoon kosher salt
1/2 teaspoon ground cardamon
10 tablespoons unsalted butter, room temperature
1 cup granulated sugar
3 eggs
1 teaspoon vanilla
1 1/4 cups plain greek yogurt
1 3/4 cups plums, pitted and chopped into 1/4 inch pieces
10-12 additional plums, pitted and quartered, to decorate the top of the cake

additional butter at room temperature to grease baking tin

for crumb topping
1 1/2 cups all purpose flour
1/2 cup packed brown sugar
1 teaspoon ground cardamon
1/2 teaspoon kosher salt
12 tablespoons unsalted butter, room temperature and cut into 1/4 inch chunks

equipment: 9 inch cake pan, round or square; rimmed baking sheet, stand or electric mixer

method

1. grease baking tin with butter and set aside. preheat oven to 350 degrees Fahrenheit.
2. make the crumb topping: in a small bowl combine the dry ingredients for the topping.
3. using your fingers, gently blend the butter chunks into the dry ingredients, working quickly so that the butter doesn't melt. continue working until the mixture resembles small coarse pebbles, and holds together if you squeeze a handful. chill the crumb topping while you make the cake.
4. in a medium bowl, whisk together the dry ingredients for the cake and set aside.
5. in the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), cream the butter with the sugar until it is pale and fluffy, about 4 minutes.
6. add the eggs, one at a time, mixing after each egg to make sure it gets integrated into the batter. add the vanilla and mix again. using a rubber spatula, scrape down the sides of the bowl and underneath the paddle to ensure even mixing.
7. begin adding the dry ingredients two spoonfuls at a time, alternating with the greek yogurt.
8. when you have about 1/4 cup of the dry ingredients left, toss the chopped plum chunks into the remaining dry ingredients to coat them.
9. remove the mixing bowl from the mixer and using the rubber spatula, gently fold in the flour coated plum chunks.
10. scrape the batter into the prepared pan and smooth the top to ensure that it is spread evenly.
11. arrange the quartered plums decoratively across the top of the cake batter. if you're using a round pan, concentric circles of plums looks quite nice. I used a square pan, so made diagonal rows of plums, beginning in one corner and continuing across the cake.
12. remove the crumb topping from the refrigerator and if necessary use a spoon to loosen it a bit. sprinkle the crumb topping across the cake, either between rows of plums or across the entire cake. I added about half of the total crumb topping mixture, and reserved the rest to make crumble the next day, but you can add as much or as little as you like.
13. place the cake onto a rimmed baking sheet and bake in the preheated oven for 50-60 minutes, rotating the baking sheet about halfway through the baking time to ensure even baking.
14. the cake is finished when it's golden brown and a skewer comes out clean after piercing.
15. set the cake on a wire cooling rack, and let cool in the pan for at least 15 minutes. at this point, you can remove the cake from the pan to finish cooling on the wire rack, or leave it in the pan until you're ready to serve.
16. wrap any uneaten cake in plastic wrap. it will stay fresh at room temperature for two days, if you don't eat it all first.

the nine inch cake can be cut into twelve or sixteen servings.