Hi Darleen - I printed this recipe some time ago - but have not tried it:
ROOTBEER COOKIES _ ROLL OUTS

1 cup margarine
1-1/2 cups confectioners sugar
1 egg
1 teaspoon vanilla
1/4 teaspoon rootbeer extract or r.b. flavored oil
2-1/2 cups flour
1/2 teasp baking soda
1/4 teasp cream of tartar

Cream margarine and sugar; beat in egg;add vanilla and rootbeer extract. Add dry ingredients (which you've previously mixed together).Wrap in plastic and chill in refrigerator 2 to 3 hours. Roll out 1/8 inch thick in shape desired (maybe rootbeer float mugs?). Bake at 375 for 5 to 7 minutes.

Icing:
1 cups confectioners sugar
3 tablespoons butter or margarine
1/4 teaspoon root beer extract
1-1/2 tablespoons milk

Combine ingredients. If desired, color brown to outline mug. Use vanilla prepared tube frosting for 'froth' at top of mug.

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Rootbeer extract is usually available in supermarkets -- in area McCormicks is BIG and the rootbeer extract is in little bottles just like vanilla, lemon and almond extract.