PASTRY:

1 1/2 c. (3 sticks) unsalted butter, at room temperature
2/3 c. sugar
2 1/2 tsp. grated lemon peel
3 c. all-purpose flour
1/2 c. cornstarch
1/2 tsp. salt

TOPPING:

10 tbsp. (1 1/4 sticks) unsalted butter
1/2 c. plus 2 tbsp. firmly packed dark brown sugar
1/3 c. honey
1 1/2 c. toasted blanched whole almonds (about 8 oz.)
1 1/2 c. salted roasted cashews (about 8 oz.)
2 1/2 tbsp. whipping cream

FOR PASTRY: Preheat oven to 350 degrees. Line 9x13 inch glass baking dish with foil. Using electric mixer, cream butter. Add sugar and lemon peel and beat until light and fluffy.

Combine flour, cornstarch, and salt in small bowl; mix to blend. Add to butter and mix until beginning to gather together. Turn out onto sheet of waxed paper; form into rectangle. Cover with another sheet of waxed paper. Roll out to 10x15 inch rectangle. Refrigerate 10 minutes.

Transfer pastry to prepared dish, discarding waxed paper. Fold and press as necessary to form 1-inch high edges. Pierce all over with fork. Bake until beginning to color, piercing with fork if pastry puffs during baking (edges will recede), about 40 minutes. Remove from oven; maintain oven at 350 degrees.

FOR TOPPING: Combine first 3 ingredients in heavy medium saucepan. Whisk over medium-high heat until mixture comes to boil. Boil without whisking until mixture thickens and bubbles enlarge, about 1 minute. Mix in almonds and cashews. Remove from heat and mix in whipping cream.

Spread topping in crust. Bake until caramel bubbles, about 20 minutes. Cool in pan on rack. Remove from pan, using foil as aid. Cut into 1 1/2 inch squares. Store in airtight container. Makes about 40.