Preheat oven to 350° F.

Microwave morsels and butter in medium, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; stir.

Microwave at additional 10- to 20-second intervals, stirring until smooth.

Stir in crumbs and nuts.

Reserve 2 cups crumb mixture; press remaining mixture into ungreased 15 x 10-inch jelly-roll pan.

Bake for 12 minutes.

Beat cream cheese and sugar in large mixer bowl until creamy.

Add eggs one at a time, beating well after each addition.

Beat in flour and lemon juice.

Pour over crust; sprinkle with reserved crumb mixture.

Bake for 20 to 25 minutes or until set.

Cool in pan on wire rack.

Cut into bars or diamonds; refrigerate.