I jazzed up my Mom's go-to recipe for coffee cake to create The Best Sour Cream Coffee Cake - with plenty of streusel and a brown butter glaze.
Preheat oven to 350 degrees.
Spray a 9×5 loaf pan with non-stick cooking spray.
With a hand or stand mixer, beat together the stick of butter and 3/4 cup sugar until pale and fluffy. Add the eggs, one a time, beating after each addition. Add the vanilla and sour cream and beat until well combined.
Whisk together the flour, baking powder, baking soda and salt. Add the dry ingredients to the butter mixture and stir by hand until no streaks of flour remain. Set the cake batter aside.
In a clean bowl, combine the brown sugar, flour, cinnamon, pinch of salt, 1 1/2 tablespoons of cold butter and 1/4 cup of the walnuts. Use a pastry cutter or two forks to cut the butter into the streusel until well combined.
Spread half the cake batter into the bottom of the loaf pan. Sprinkle half the streusel on top of the batter. Top the streusel with the remaining cake batter and spread to smooth the top. Sprinkle the remaining streusel on top. And top with the remaining 2 tablespoons of chopped walnuts.
Bake the bread on the center rack of the oven for 50 minutes, or until loaf springs back when the top is lightly pressed.
While the bread is baking, heat a small skillet over medium heat. Add the remaining 3 tablespoons of butter. Melt the butter and swirl the pan until the butter smells “nutty” and is browned. Remove from heat.
Whisk together the powdered sugar, browned butter and milk to form a smooth glaze.
Pour the glaze over the top of the bread when it comes out of the oven.
Allow the bread to cool, slice and serve.