Preheat your oven to 350°F and grease a 9x13-inch baking pan with butter or cooking spray. Line the bottom with parchment paper for easier removal if desired. This step ensures even heat circulation and prevents sticking.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy, approximately 3-4 minutes. Beat in the eggs one at a time, then add vanilla extract and mix until fully combined. This builds the foundation for your warm comforting brunch centerpiece.

In a separate bowl, whisk together flour, baking powder, baking soda, and salt. Alternate adding the dry mixture and sour cream to the wet ingredients, beginning and ending with dry ingredients. Stir until just combined—do not overmix, as this toughens the cake.

Pour the batter into your prepared pan and smooth the top with a spatula. In a small bowl, combine brown sugar, cinnamon, pecans, and melted butter to create the streusel. Sprinkle this mixture evenly across the cozy coffee cake brunch recipe surface, pressing gently to adhere.

Bake for 35-40 minutes, until a toothpick inserted in the center comes out clean or with just a few moist crumbs. The top should be golden brown and the streusel fragrant. Allow it to cool in the pan for 10-15 minutes before serving, which lets the structure set properly.