Bars o' Gold

1 1/2 cups firmly packed brown sugar
1 cup quick oats
3/4 cup flour
1/2 teaspoon salt
1/4 teaspoon baking soda
1/2 cup margarine
1 egg
1 tablespoon lemon juice
1 teaspoon vanilla extract
1/2 cup chopped walnuts

Combine all ingredients except nuts in a large mixer bowl. Mix at low speed until well blended; stir in nuts. Pour into greased 8-inch square pan. Bake at 350 degrees F for 40 to 45 minutes. Do not overbake. Cut into squares after cooling.