1 cup granulated sugar
2/3 cup packed light brown sugar
2 cups pecans, toasted and chopped
1/3 cup all-purpose flour
2 tablespoons pure vanilla extract
2 teaspoons ground cinnamon
4 tablespoons unsalted butter, melted

2 1/2 cups all-purpose flour
1 teaspoon baking soda
3/4 teaspoon salt
1 1/4 cups sour cream
1 tablespoon pure vanilla extract
12 tablespoons unsalted butter, softened
1 1/4 cups granulated sugar
3 large eggs, room temperature


Heat oven to 350°F. Line bottom of a 9-in. square cake pan with parchment paper; butter paper and sides of pan.

Combine sugars, pecans, flour, pure vanilla and cinnamon in a small bowl. Add butter and stir to make moist, coarse crumbs. Set aside.

1. Sift flour, baking soda and salt into a medium bowl. Mix sour cream with vanilla in a small bowl. Beat butter and sugar in a large bowl with an electric mixer on medium speed until light, about 5 minutes. Add eggs 1 at a time, beating well after each addition. Add flour mixture in 3 parts, alternating with sour cream mixture in 2 parts, beginning and ending with the flour.

2. Spread 2/3 of the batter in the prepared pan and sprinkle ½ the crumbs over the top. Spoon the remaining batter in mounds on top, then spread it out evenly. Sprinkle the rest of the crumbs over cake and bake until the top is brown and a toothpick inserted in the center comes out clean, about 1 hour. If the top gets dark, cover with foil and continue to cook until the inside is cooked through. Cool cake in pan on a rack for 20 minutes, then turn it out of the pan, invert and cool.