MIX graham crumbs and butter. Press 1 cup of the crumb mixture firmly onto bottom of 9-inch square pan. Set remaining crumb mixture aside.
COMBINE strawberries, dry jelly powder, sugar and lemon extract in medium saucepan; bring to boil on medium-high heat. Reduce heat to low; simmer 3 min. or until jelly powder is dissolved, stirring occasionally. Remove from heat. Cool 20 min. to room temperature. Gently stir in 1-1/2 cups of the whipping topping; pour over crust.
REFRIGERATE 3 hours or until firm. Cover with remaining whipped topping; sprinkle with remaining crumb mixture. Cut into 24 pieces to serve. Store leftover dessert in refrigerator.