Chop first 3 ingredients coarsely. Place in a shallow pan.
Bake at 350° for 5 to 7 minutes or until toasted, stirring once. Set aside.
Pulse flour, 1/4 cup brown sugar, and 6 tablespoons butter in a food processor 7 to 8 times or until mixture is crumbly. Add 1 egg; pulse 4 to 5 times or until dough forms a ball. Press dough into bottom and up sides of an 11-inch tart pan with removable bottom. Freeze 2 hours.
Stir together remaining 1 cup brown sugar, remaining 3 eggs, apricots, and next 5 ingredients. Stir in nuts; pour into crust.
Bake at 350° on bottom oven rack for 35 to 40 minutes or until set. Cool on a wire rack. Serve with ice cream, if desired. Garnish, if desired.