Custard-filled Walnut-topped Cake

Ingredients

• 1 teaspoon double-acting baking powder 
• 0.5 teaspoon baking soda 
• 0.5 cup brown sugar light packed
• 0.3 cup butter melted softened at room temperature
• 1.5 tablespoons cornstarch 
• 3 large eggs divided
• 2 cups flour all-purpose
• 1.3 cups granulated sugar divided
• 0.3 teaspoon nutmeg 
• 1 cup milk 
• 0.5 teaspoon salt 
• 1 cup cream sour
• 1 teaspoon vanilla extract 
• 0.5 cup walnut pieces chopped

Equipment

• bowl
• frying pan
• sauce pan
• oven
• knife
• whisk
• toothpicks
• cake form
• serrated knife

Directions

1. Preheat oven to 35
2. Coat a 9-in. round cake pan with 2-in. sides with cooking-oil spray.
3. Mix walnuts, brown sugar, melted butter, and nutmeg and spread into pan.
4. In a large bowl, cream 1 cup granulated sugar with softened butter. Beat in 2 eggs.
5. In a medium bowl, mix flour, baking powder, baking soda, and 1/4 tsp. salt. Beat 1/3 flour mixture into butter mixture, then 1/2 cup sour cream; repeat with another 1/3 flour mixture, then remaining sour cream and flour mixture. Spoon evenly into pan.
6. Bake cake until a toothpick inserted in center comes out clean, 40 to 50 minutes. Cool in pan 10 minutes. Run a thin knife around pan edge to loosen cake; invert onto a rack.
7. Let cool completely, then slice in half horizontally with a serrated knife.
8. In a saucepan, mix remaining granulated sugar, the cornstarch, remaining salt, and milk. Stir over medium heat until thickened, 5 minutes.
9. Remove from heat.
10. In a small bowl, lightly beat remaining egg with about 1/3 cup hot milk mixture. Return it to milk mixture in pan and stir over medium heat until hot and very thick, 1 to 2 minutes. Stir in vanilla.
11. Remove custard from heat and whisk often until cool, at least 20 minutes.
12. Set bottom layer of cake, cut side up, on a serving platter.
13. Spread custard over cake, then top with remaining layer, nut side up.