Preheat your oven to 350 degrees Fahrenheit.

In a mixing bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then fold in the sour cream and vanilla.

Sift together the flour, baking powder, and salt. Fold this mixture into the wet ingredients until just combined.

Spread half of the batter over the bottom of a buttered and floured 10-inch springform pan. Combine the topping ingredients (pecans, sugar, and cinnamon) in a small bowl. Sprinkle three-quarters of this mixture over the batter in the pan. Top with the remaining batter and sprinkle with the remaining pecan topping.

Bake in the preheated oven until a wooden toothpick inserted into the center comes out clean, about 1 hour.

Allow the cake to cool thoroughly before wrapping.