Maple Walnut Crumb Cake

INGREDIENTS

• 5 cups all-purpose flour
• 3 cups white sugar
• 1/2 teaspoon salt
• 3 1/2 teaspoons baking powder
• 3 eggs
• 1 1/4 cups vegetable oil
• 1 1/8 cups milk
• 1 teaspoon vanilla extract
• 1 teaspoon maple flavored extract
• 1/2 cup butter, softened
• 1 tablespoon ground cinnamon
• 1/4 cup ground walnuts
• 1 cup chopped walnuts
• confectioners' sugar for dusting