A classic Bundt coffee cake with a tender, moist sour cream crumb and a hidden swirl of cinnamon, sugar, and chopped nuts running through the middle. Layer the filling and batter twice in the pan, bake for an hour, and invert. Simple, time-honored, and the kind of thing Granny Buras brought to every gathering.
Do not overbeat after adding the eggs — overmixing makes the crumb tough. Stir just until combined.