This loaf transforms the classic coffee cake into a perfectly sliceable, shareable format. It features a supremely moist and tender sour cream cake base, a sweet cinnamon-sugar ribbon running through the center, and a generous crown of buttery, crunchy streusel topping.
Baked in a standard loaf pan, it’s easier to serve than a tube cake and makes for the ultimate cozy treat alongside your morning coffee or afternoon tea.
The Science of Moist Cake & A Crunchy, Stable Streusel
The exceptional tenderness of this cake comes from two key ingredients: sour cream and oil. The acidity in sour cream tenderizes gluten, while its fat content adds richness and moisture.
Using oil instead of butter in the batter ensures the crumb stays incredibly soft and moist for days. The streusel topping needs to be crunchy and clumpy, not sandy or melted. This is achieved by using cold butter cut into the dry ingredients, creating pea-sized crumbs that bake up crisp.
A portion of the streusel is also mixed with cinnamon to create the flavorful inner ribbon, which stays distinct because it’s layered between thicker batter.
Ingredients
For the Cinnamon-Sugar Ribbon:
- ¼ cup (50g) granulated sugar
- 1 ½ teaspoons ground cinnamon
For the Streusel Topping:
- ½ cup (100g) packed light brown sugar
- ½ cup (63g) all-purpose flour
- 1 teaspoon ground cinnamon
- ¼ teaspoon salt
- ¼ cup (½ stick / 57g) cold unsalted butter, cubed
For the Cake Batter:
- 2 cups (250g) all-purpose flour
- 2 teaspoons baking powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- ¾ cup (150g) granulated sugar
- ½ cup (100g) packed light brown sugar
- ½ cup (120ml) vegetable or canola oil
- 2 large eggs, room temperature
- 1 cup (240g) full-fat sour cream, room temperature
- 2 teaspoons vanilla extract
Instructions
1. Make the Cinnamon Ribbon & Streusel: In a small bowl, mix ¼ cup sugar with 1 ½ tsp cinnamon for the ribbon; set aside. For the streusel, in a separate bowl, combine brown sugar, flour, 1 tsp cinnamon, and salt. Cut in the cold butter with a pastry cutter or your fingers until the mixture resembles coarse crumbs with some pea-sized clumps. Set aside.
2. Prepare Pan & Oven: Preheat oven to 350°F (175°C). Grease a 9×5-inch loaf pan and line it with parchment paper, leaving an overhang on the long sides for easy removal.
3. Make the Cake Batter: In a medium bowl, whisk flour, baking powder, baking soda, and salt. In a large bowl, whisk granulated sugar, brown sugar, and oil until combined. Whisk in eggs one at a time, then sour cream and vanilla until smooth. Gently fold the dry ingredients into the wet ingredients with a spatula until just combined and no flour streaks remain.
4. Layer the Batter, Ribbon, and Streusel: Spoon half of the batter into the prepared loaf pan and smooth the top. Sprinkle the entire cinnamon-sugar ribbon evenly over the batter. Spoon the remaining batter over the ribbon and smooth carefully. Sprinkle all of the prepared streusel topping evenly over the final layer of batter, pressing it down lightly so it adheres.
5. Bake Until Golden: Bake for 55-70 minutes, or until a toothpick inserted into the center of the cake (avoiding the gooey ribbon) comes out clean. If the streusel is browning too quickly, tent the loaf loosely with foil for the last 15 minutes of baking.
6. Cool, Slice & Serve: Let the cake cool in the pan on a wire rack for 30 minutes. Then, use the parchment overhang to lift it out of the pan and transfer to the rack to cool completely before slicing. This allows the structure to set for clean slices. Serve at room temperature.
Pro-Tips for the Ultimate Coffee Cake Loaf
- Room Temperature Ingredients: Using room temperature eggs and sour cream ensures a smooth, evenly mixed batter that bakes consistently.
- Don’t Overmix: Fold the dry ingredients just until combined. Overmixing develops gluten and leads to a tough cake.
- Cold Butter for Streusel: This is essential for achieving a clumpy, crisp topping. If the butter melts, the streusel will be sandy and may sink.
- Check for Doneness Carefully: Test with a toothpick in the cake portion, not the cinnamon-sugar ribbon, as it will remain moist.
- Cool Completely: The cake needs time to set. Slicing it while warm will cause it to crumble.
- Storage: Store leftovers covered at room temperature for up to 3 days, or freeze the whole loaf for up to 2 months.
This Classic Cinnamon Streusel Coffee Cake Loaf is a timeless, comforting bake that never disappoints.