1
: Preheat oven to 350ºF (180ºC). Line a 9" x 9" (2L) baking dish with parchment paper.
2
: Toast nuts if desired. In food processor, finely grind 1 ½ cups (375mL) nuts with sugar. Combine melted butter; press firmly on bottom of prepared baking dish.
3
: Bake in preheated oven 18 minutes or until edges are golden.
4
: Meanwhile bring sweetened condensed milk and remaining 2 tbsp (30mL) butter to a boil over medium-low heat, stirring constantly for 5 minutes or until mixture thickens. Remove from heat and stir in vanilla. Spoon over hot crust. Bake 12 minutes or until golden.
5
: Remove from oven and immediately sprinkle with chocolate chunks. Let stand 2 minutes; spread chocolate evenly over top. Sprinkle with remaining ½ cup (125mL) chopped nuts. Cool on wire rack; refrigerate until set, at least 4 hours. Cut into diamonds or squares. Refrigerate or freeze in airtight container.