Ingredients:
For The Topping:
1/2 cup walnut halves, coarsely chopped
1/2 cup pecan halves, coarsely chopped
2/3 cup all-purpose flour
1/3 cup granulated sugar
1/3 cup packed light brown sugar
2 tsp ground cinnamon
1 tsp kosher salt
5 Tbsp. unsalted butter, melted
For The Cake:
4 tbsp. (½ stick) unsalted butter, plus more for the pan
1 cup granulated sugar
2 large eggs, room temperature
2 cups all-purpose flour
1 tsp. baking powder
1 tsp. baking soda
1 tsp. kosher salt
1 cup sour cream
1/2 cup whole-milk yogurt
To Make The Topping:
Line a baking sheet with parchment paper.
Set aside.
In a medium bowl, stir together the walnuts, pecans, flour, granulated and brown sugars, cinnamon, and salt.
Stir in the butter.
The topping should bits and clumps.
Sprinkle the topping onto the baking sheet.
Break the large clumps up into smaller clumps.
Refrigerate.
Preheat the oven to 350 F.
Grease the bottom and the sides of a 9-inch round baking pan with butter.
Set aside.
To Make The Cake Batter:
In the bowl of a stand mixer fitted with the whisk attachment, beat the butter and sugar together, on medium-high.
Scrape down the sides from time to time.
Mix for about 8 minutes.
Lower the speed and add the eggs, one by one.
Be sure each egg is thoroughly mixed in before adding the next.
Sift together the flour, baking powder, and baking soda.
In a separate bowl, whisk together the salt, sour cream and yogurt until smooth.
Turn the mixer on low and alternate adding the flour mixture with the sour cream mixture.
When all has been mixed together, scrape the bottom and sides of the bowl to be sure the batter is thoroughly combined.
Transfer the batter to the greased baking pan.
Tap it lightly on the sides so the batter is even. in the pan.
Sprinkle the cake, using all of the topping.
Bake until a cake tester or a small knife inserted in the center comes out clean, about 55-60 minutes. Allow the cake to cool for at least 15 minutes before slicing.
The cake will keep, covered, for up to 3 days.