Generously butter and flour a 12 cup bundt pan. Preheat the oven to 350 degree.
In a large mixing bowl, using an electric mixer, cream together the butter and 2 cups of the sugar.
Add eggs, blending well after each addition, then the sour cream and vanilla.
In a medium bowl, sift together flour, baking powder, add salt.
Fold the flour mixture into the creamed mixture, and mix just until blended. Do not overmix
In a small bowl, mix remaining 3/4 cup sugar with pecans and cinnamon.
Pour half of the batter into the prepared pan, then top with half of the pecan and sugar mixture. Add remaining batter and sprinkle the top with remaining pecan mixture.
Place the cake on the center rack in preheated oven and bake until a cake tester inserted in 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 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