Use a 9 x 5" loaf pan for this cake. If you only have the 8 x 4 inch pan, hold back about 3/4 cup of the batter and use it to make a few muffins. Ground walnuts and cinnamon make this heavenly loaf unlike any other!
Cut a piece of parchment paper to fit the bottom of the pan. Spray a loaf pan (9" x 5" x 3") liberally with non-stick vegetable spray. Lay the parchment paper in the bottom of the pan and spray again. Set aside.
Place the walnuts on a baking pan and toast for 10-15 minutes or until fragrant and lightly browned.
In a food processor add 1/2 cup + 1 tablespoon toasted walnuts and 1/2 cup sugar. Pulse until the walnuts are finely ground and set aside.
In a medium bowl, combine the flour, baking powder, baking soda, kosher salt and cinnamon. Whisk to combine and set aside.
Combine the milk, sour cream and vanilla in a small bowl and whisk to combine.
In a large bowl add the butter and remaining half cup of sugar. Beat the butter and sugar together with a hand mixer on high speed until light and fluffy, about 4-6 minutes, scraping the sides of a bowl with a rubber spatula occasionally.
Add the eggs one at a time and beat into the butter mixture until fully incorporated before adding the second egg. Beat until blended and the mixture is light and fluffy.
Alternating adding half the flour mixture with half the sour cream mixture, beating into the butter mixture until just combined. After the dry and wet ingredients have been blended, stir in the ground walnuts to combine evenly. Transfer the batter to the prepared pan --
Bake for 45 minutes or until a cake tester comes out clean.
Let the loaf rest in the pan for about 20-30 minutes before transferring to a cooling rack.
FOR THE GLAZE AND DECORATION:
In a small bowl, whisk together the powdered sugar and 1 teaspoon of milk at a time until a thick, pourable glaze forms. Typically it's 4 teaspoons for me, but it could be more or less for you, depending on where you live and the climate.
Finely chop the remaining walnuts.
Pour the glaze over the cooled loaf cake and sprinkle on the chopped walnuts. Let the glaze set before cutting into slices.
Notes
If you have the smaller and more common 8.5 x 4.5 x 2.5 loaf pan, there will be a little too much batter and the pan will overflow (ask me how I know that). Reserve some of the batter from the loaf and make a few muffins on the side (Muffins should take anywhere from 15-20 minutes to bake, depending on the size of your muffin tin.) Check doneness after the first 12-15 minutes with a cake tester. If you poke it into the center of the muffins and it comes out clean, they're done.