▢2½ cups all purpose flour
▢1 tablespoon baking powder
▢½ teaspoon baking powder (total 1 tablespoon + ½ teaspoon)
▢½ teaspoon salt
▢¾ cup butter
▢1½ cups dark brown sugar packed
▢3 tablespoons canola oil
▢2 teaspoons vanilla
▢4 eggs large
▢1¼ cups milk
▢1 cup butterscotch chips
▢2 tablespoons butter
▢3 cups powdered sugar
▢5 tablespoons milk
Prepare your sheet pan with baking spray to grease the bottom and sides. Preheat oven to 350°F.
In a medium mixing bowl, combine flour, baking powder and salt. Set aside.
In a large mixing bowl or stand mixer, add butter, dark brown sugar and canola oil. Beat until light in color and fluffy, about 3-4 minutes.
Add eggs and vanilla extract and mix until combined.
Add milk and blend to combine.
Gradually add dry mixture to wet until just combined and smooth. Don’t overmix.
Bake in a jelly roll pan for a thinner sheet cake 15 minutes. In a 9×13 baking dish, bake 30 minutes or until a toothpick inserted in the center of the cake comes out clean.
Remove cake and place on a wire cooling rack to cool.
Melt butterscotch chips and butter together in a microwave safe bowl. Start with one minute and then melt in 10 second increments, so you don’t burn or overcook.
Add melted butterscotch and butter mixture to a large mixing bowl or stand mixer.
Alternate adding powdered sugar and milk until fully combined.
Spread onto cooled cake.