1. Heat oven to 350°F. Grease 13x9x2-inch baking pan.
2. Stir together flour, baking powder, baking soda and salt. Beat butter and brown sugar in large bowl until light and fluffy. Add eggs, milk and vanilla; beat well. Gradually add flour mixture, beating well. Stir in small chocolate chips. Spread in prepared pan.
3. Bake 30 to 35 minutes or until lightly browned. Cool in pan on wire rack. Cut into bars. Makes 24 to 36 bars.
HIGH ALTITUDE DIRECTIONS:
- Increase flour to 2 cups plus 2 tablespoons
- Decrease baking powder to 3/4 teaspoon
- Decrease packed light brown sugar to 1-1/4 cups
- Increase milk to 1/4 cup
- Bake at 350°F, 27 to 32 minutes