Chocolate Cake with Milk Chocolate-Peanut Butter Frosting and Peanut Butter Brittle

Nonstick vegetable oil spray

3 cups all purpose flour

2 cups sugar

2/3 cup sifted natural unsweetened cocoa powder (sifted, then measured)

2 teaspoons baking soda

1 teaspoon salt

2 cups water

2/3 cup vegetable oil

2 tablespoons apple cider vinegar

2 teaspoons vanilla extract Brittle:

Vegetable oil

1 cup sugar

1/2 cup light corn syrup

1/4 cup water

1 cup chopped lightly salted dryroasted peanut s

1 teaspoon creamy (smooth) natural peanut butter (made with only peanuts and salt)

1/2 teaspoon baking soda

1/2 teaspoon vanilla extract Filling and frosting:

4 ounces imported milk chocolate, chopped

5 tablespoons heavy whipping cream

2 

1/4 cups powdered sugar

1 

1/2 cups chilled heavy whipping cream

3/4 cup creamy (smooth) natural peanut butter (made with only peanuts and salt)

3/4 cup chilled mascarpone cheese*