PREHEAT oven to 350° F. Grease 8-inch-square baking pan.
MELT 1 cup morsels and butter in small saucepan over low heat, stirring occasionally until morsels are melted and mixture is smooth. Remove from heat; cool to room temperature, about 15 minutes.
WHISK sugar and eggs in large bowl until thick and lemon colored. Gradually beat in chocolate mixture and vanilla extract. Combine whiskey and coffee granules in small cup; stir until dissolved. Add to chocolate mixture. Gradually stir in flour. Pour into prepared pan.
BAKE for 25 to 30 minutes or until wooden pick inserted near center comes out clean. Immediately sprinkle with remaining 3/4 cup morsels. Let stand for 5 minutes or until morsels are shiny and soft; spread evenly. Cool completely in pan on wire rack. Cut into squares.
*Note: An additional 1 1/2 teaspoons of vanilla extract plus 4 1/2 teaspoons water can be substituted for the Irish whiskey.