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

 * 1) Heat oven to 350°F.
 * 2) Beat butter and brown sugar in large bowl until well blended. 
 * 3) Add eggs, vanilla and instant coffee, if desired; beat until fluffy.
 * 4) Stir together oats, flour, baking soda, salt and 1 cup walnuts; gradually stir into butter mixture with spoon. 
 * 5) Set aside 2 cups dough.
 * 6) Press remaining dough evenly onto bottom of ungreased 15-1/2x10-1/2x1-inch jelly roll pan. 
 * 7) Prepare CHOCOLATE FILLING; spread evenly over dough. 
 * 8) Crumble reserved dough evenly over filling. 
 * 9) Sprinkle with remaining 1/2 cup walnuts.
 * 10) Bake 25 minutes or until top is golden brown (chocolate will be soft). 
 * 11) Cool completely in pan on wire rack; cut into bars. 
 * 12) About 4 dozen bars.
 * 13) =====CHOCOLATE FILLING=====
 * 14) Melt butter in medium saucepan over low heat. 
 * 15) Stir in cocoa and sugar. 
 * 16) Add sweetened condensed milk; cook, stirring constantly, until smooth and thick.
 * 17) Remove from heat.
 * 18) Stir in vanilla.