This classic coffee cake is moist, tender, and topped with a delicious streusel crumb. Perfect for breakfast or as an afternoon treat with a cup of coffee, this cake is sure to become a favorite!

Ingredients
For the Cake:
- 2 cups all-purpose flour
- 1 cup granulated sugar
- 1/2 cup unsalted butter, softened
- 1 cup sour cream (or plain yogurt)
- 2 large eggs
- 1 teaspoon vanilla extract
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
For the Streusel Topping:
- 1/2 cup all-purpose flour
- 1/2 cup brown sugar, packed
- 1 teaspoon ground cinnamon
- 1/4 cup unsalted butter, melted
- 1/2 cup chopped nuts (optional, such as walnuts or pecans)







Instructions
1. Preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan or line it with parchment paper.
2. In a medium bowl, mix together the ingredients for the streusel topping: flour, brown sugar, ground cinnamon, and melted butter. Stir in the chopped nuts if using. Set aside.
3. In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy. Add the eggs, one at a time, mixing well after each addition. Stir in the sour cream and vanilla extract until combined.
4. In a separate bowl, whisk together the dry ingredients for the cake batter: flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, mixing until just combined. Do not overmix.
5. Pour half of the cake batter into the prepared baking pan and spread it evenly. Sprinkle half of the streusel topping over the batter. Pour the remaining cake batter on top and spread evenly, then finish with the remaining streusel topping.
6. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
7. Allow the coffee cake to cool in the pan for about 10-15 minutes, then transfer to a wire rack to cool completely.

