Creamy Jammy Coffee Cakes

Position an oven rack in the middle of the oven and preheat the oven to 350F [180C]. Grease eight 4 in [10 cm] cake pans or springform pans, and line the bottoms with parchment paper. Or prepare a jumbo muffin pan or ramekins (see note).

In a medium bowl or liquid measuring cup, whisk together the sour cream, buttermilk, egg, and vanilla.

In the bowl of a stand mixer fitted with a paddle, combine the flour and granulated sugar on low speed. Add the butter, one piece at a time, beating until the mixture resembles coarse sand. Remove 1 cup [130 g] of the mixture and set it aside in a small bowl.

With the mixer on low speed, beat in the baking powder, baking soda, and salt. Add the wet ingredients and mix until incorporated, about 30 seconds. Remove the bowl from the mixer. Scrape down the sides of the bowl and use a spatula to mix the batter a few more times. Divide the batter evenly among the prepared pans and smooth the tops with an offset spatula or the back of a spoon. Spread 2 tablespoons of jam evenly over the cake batter in each pan.

For the filling: In the stand mixer bowl in which you mixed the cake batter, beat together the cream cheese and granulated sugar on low speed until smooth and creamy. Add the egg and mix until incorporated, scraping down the sides as needed. Divide the cream cheese mixture among the pans and smooth the tops with an offset spatula or the back of a spoon. Divide the reserved flour-butter mixture among the pans, sprinkling it evenly over the tops. Tap the pans gently on the counter twice to help get rid of any air bubbles.

Place the cake pans on a large sheet pan and bake until golden brown and a wooden skewer or toothpick inserted into the center comes out with a few crumbs, rotating the pan halfway through baking, 26 to 32 minutes. Transfer the pans to a wire rack and let the cakes cool until barely warm or at room temperature.

Remove the cakes from their pans and serve. Alternatively, the cakes can be covered in plastic wrap after cooling and stored in the refrigerator overnight.