Chocolate Bundt Cake with Sweet Walnut Layer

You can't go wrong with a Chocolate Bundt Cake, and this one is particularly good because it has sweet walnut layer. I first saw this recipe on Fine Cooking.  I made a few changes, but the essence is there. I'm sure you'll make a few, too. The original recipe called for plain yogurt. I've made this bundt cake with Greek yogurt...a little tangy, but still tasty. I think I prefer sour cream for the richness, but you try it both ways!

Chocolate Bundt Cake with  Sweet Walnut Layer

1 1/4 cups all purpose four
3/4 cup dark cocoa
Dash of Salt
1 tsp baking soda
1 tsp baking powder
2 tbsp sweet butter, melted
2 tbsp canola oil
2 eggs
2 egg whites
1 1/2 cups sour cream
2 tsp Madagascar vanilla extract
3/4 cup sugar
3 ounces of dark chocolate (70-85% cacao) I like it really dark
1 tbsp powdered sugar-optional

Walnut Layer
1/3 cup chopped walnuts
1/3 cup dark brown sugar
2 tbsp sweet butter, melted

Preheat oven to 350.
Oil bundt pan.
Whisk in bowl flour, cocoa, salt, baking powder and soda. Then sift into another bowl.
In a different bowl, whisk melted butter and oil, and then add eggs and egg whites.
Fold in sour cream, vanilla extract and sugar.
Melt the chocolate in a double boiler or in a saucepan over a saucepan with water.
Fold chocolate into batter.
Add dry ingredients and stir until combined. Do not overmix.
Mix melted butter, walnut and brown sugar together.
Pour half of the batter into the pan and place the walnut layer on top of the batter.
Fill with remaining batter.
Bake 35-45 minutes, until a toothpick comes out clean.
Cool on wire rack in the pan for 15 minutes and then, flip it over on the rack.
Top with powder sugar (optional)