Generously butter and flour a 12-cup bundt pan. Preheat the oven to 350ºF (177ºC).
In a large mixing bowl, using an electric mixer, cream together the butter (16 tablespoons) and 2 cups of the sugar.
Add eggs (2), blending well after each addition, then the sour cream (2 cups) and vanilla (1 tablespoon).
In a medium bowl, sift together flour (2 cups), baking powder (1 tablespoon), and salt (1/4 teaspoon).
Fold the flour mixture into the creamed mixture, and mix just until blended. Do not overmix.
In a small bowl, mix the remaining 3/4 cup of sugar with pecans (2 cups) and cinnamon (1 tablespoon).
Pour half of the batter into the prepared pan, then top with half of the pecan and sugar mixture. Add the remaining batter and sprinkle the top with the remaining pecan mixture.
Place the cake on the center rack in the preheated oven and bake until a cake tester inserted in the center of the cake comes out clean, about 60 minutes.
Let cool on a wire rack for at least 30 minutes. Carefully transfer the cake to a serving plate.
Meanwhile, prepare the glaze. In a medium mixing bowl, whisk the powdered sugar (1 cup) and 2 tablespoons of milk together until smooth. Add more milk as necessary to obtain a pouring consistency. Drizzle glaze over cooled coffee cake. Garnish with chopped pecans (3/4 cup).
Notes
Let the cake cool before glazing. If the bundt is warm, the glaze will disappear like magic — soaking right in. Delicious, but not decorative.
Check for doneness with a spaghetti noodle. A clever backup when you don’t have a cake tester handy!
Use a heavy, quality bundt pan. It distributes heat evenly so the cake bakes with a perfect golden crust.
Don’t rush the creaming step. Light, fluffy butter and sugar = a lighter, fluffier cake.