|Butter/Margarine||1⁄2 Cup (8 tbs), softened|
|Light brown sugar||1⁄2 Cup (8 tbs), firmly packed|
|Vanilla extract||1 Teaspoon|
|All purpose flour||1⁄2 Cup (8 tbs)|
|Quick cooking oats||1⁄2 Cup (8 tbs) (Not Instant)|
|Semisweet chocolate square||3|
|Semi-sweet chocolate square||2|
|Confectioners sugar||1 1⁄2 Cup (24 tbs), sifted|
|Hot water||3⁄4 Cup (12 tbs)|
1. Preheat oven to 375°F.. Lightly grease a 13-by-9-by-2-inch pan. Line bottom with foil.
2. Make Cookie Crust: In large bowl, with wooden spoon or portable electric mixer at medium speed, beat 1/2 cup butter, the brown sugar, egg yolk and vanilla until smooth.
3. Add flour and oats; stir until well combined.
4. Press mixture evenly in bottom of prepared pan.
5. Bake 15 minutes, or until golden. Cool slightly.
6. Meanwhile, make Topping: Melt 3 squares chocolate and 1 tablespoon butter over hot, not boiling, water.
7. Spread over warm cookie crust.
8. With sharp knife, cut into bars while still warm. Let cool completely in pan before removing.
9. Meanwhile, make Frosting: In top of double boiler, over hot water, melt chocolate and butter. Remove from water; stir in confectioners' sugar and hot water, mixing until smooth. Refrigerate, covered, about 10 minutes. Put frosting into pastry bag with number-27 tip.