Heat oven to 350˚F. Grease bottom and sides of 8-inch square pan with shortening.
In 1½-quart saucepan, melt butter over low heat; remove from heat after completely melted. Stir in brown sugar, vanilla, milk and egg. Stir in remaining ingredients. Spread in pan. Sprinkle mini chocolate chips evenly on top on the mixture.
Bake about 23 minutes or until golden brown. Cool 5 minutes in pan on cooling rack. Cut into 4 by 4 rows while warm.