This Easy Blackberry Coffee Cake with Sour Cream has a soft cake bottom studded with juicy plump blackberries, a blackberry jam swirl all throughout the entire cake, with a buttery streusel topping.
Preheat the oven to 350 degrees F. Line a 9-inch springform pan with parchment paper or spray with nonstick baking spray.
Now make the streusel topping - combine all purpose flour, brown sugar, sugar, and a pinch of salt in a medium bowl. Mix together then pour in melted butter and mix together until crumbles begin to form. Place into the refrigerator.
In a large bowl, combine the dry ingredients - all purpose flour, baking powder, kosher salt, and nutmeg. Whisk together and set aside.
In a separate bowl, add room temperature butter, vegetable oil, and sugar. Use an electric hand mixer to cream together on medium speed for 2-3 minutes, until light and fluffy. Add in eggs, one at a time, ensuring each egg is fully incorporated prior to adding the next, then add in vanilla extract and sour cream and continue to mix until combined (it may separate a bit, this is perfectly normal).
Add the blackberries to the flour mixture and gently toss so that the blackberries are coated. Fold the blackberry/flour mixture into the wet ingredients with a silicone spatula or wooden spoon until combined.
Pour the cake batter into the pan and dollop blackberry preserves on top. Use a toothpick or a butter knife to gently swirl the preserves into the batter, then remove the crumb topping from the refrigerator and sprinkle on top.
Bake for 55-65 minutes, until a wooden skewer inserted into the center of the cake comes out with just a few moist crumbs. Let the cake cool in the pan for 20 minutes, then remove onto a wire rack to cool completely.
Notes
Make sure that everything is room temperature - including the blackberries! Use room temperatureButter, eggs, and sour cream to ensure a smooth batter and even rise.
Don’t overmix the batter: Once you add the dry ingredients, mix until just combined. Overmixing develops gluten and can lead to a tough, dry cake.
Let it rest before slicing: Once baked, allow the cake to cool at least 30 minutes. The crumb will set and the flavors will settle, especially with juicy fruit involved.
Place crumble topping into the refrigerator to prevent it from baking right into the cake. While it bakes, the cold butter will form a layer and prevent the streusel from becoming mushy and baking right into the batter.