Chocolate-filled Walnut-Oatmeal Bars

Ingredients

 * 1 	cup  	(2 sticks) butter or margarine, softened
 * 2 	cups 	Packed light brown sugar
 * 2 		Eggs
 * 1 	tsp 	Vanilla extract
 * 1/2 	tsp 	Powdered instant coffee (optional)
 * 3 	cups 	Quick-cooking rolled oats
 * 2 1/2 	cups 	All-purpose flour
 * 1 	tsp 	Baking soda
 * 1/2 	tsp 	Salt
 * 1 1/2 	cups 	Chopped walnuts, divided
 * CHOCOLATE FILLING (recipe follows)
 * 1/2 	cup 	(1 stick) butter or margarine
 * 2/3 	cup 	HERSHEY'S Cocoa
 * 1/4 	cup 	Sugar
 * 1 	can 	(14 oz) sweetened condensed milk (not evaporated milk)
 * 1 1/2 	tsp 	Vanilla extract

Directions
Heat oven to 350°F. Beat butter and brown sugar in large bowl until well blended.  Add eggs, vanilla and instant coffee, if desired; beat until fluffy. Stir together oats, flour, baking soda, salt and 1 cup walnuts; gradually stir into butter mixture with spoon.  Set aside 2 cups dough. Press remaining dough evenly onto bottom of ungreased 15-1/2x10-1/2x1-inch jelly roll pan.  Prepare CHOCOLATE FILLING; spread evenly over dough.  Crumble reserved dough evenly over filling.  Sprinkle with remaining 1/2 cup walnuts. Bake 25 minutes or until top is golden brown (chocolate will be soft).  Cool completely in pan on wire rack; cut into bars.  About 4 dozen bars.

CHOCOLATE FILLING
Melt butter in medium saucepan over low heat.  Stir in cocoa and sugar.  Add sweetened condensed milk; cook, stirring constantly, until smooth and thick. Remove from heat. Stir in vanilla.