Chewy Black and White Brazil Nut Bars

Brazil nuts give these two-tone bars a great texture, but feel free to substitute almonds or hazelnuts in this recipe.
Ingredients:
1 cup all-purpose flour
1/3 cup brown sugar, packed
1/2 cup ground brazil nuts, about 12 large nuts
8 ounces cold butter, cut into small pieces
1/2 teaspoon vanilla extract
.
Filling:
2 large eggs
1/2 cup brown sugar, packed
1/2 cup light corn syrup
2 tablespoons melted butter
1 teaspoon vanilla extract
1 cup semisweet chocolate chips
1/2 cup white chocolate chips
1 cup sliced or chopped brazil nuts
Preparation:
Butter a 9-inch square baking pan. Heat oven to 350°.
In a food processor, grind flour, 1/3 cup brown sugar, and ground brazil nuts together until fine. Add 1/2 teaspoon vanilla and cold butter; pulse until well blended. The mixture will appear dry and crumbly. Or, work the mixture together with a pastry blender until well blended and crumbly.

Press the crumb mixture evenly into the prepared baking pan. Bake for 10 to 12 minutes, or until lightly browned around edges.

Whisk together the eggs, 1/2 cup brown sugar, corn syrup, melted butter, 1 teaspoon vanilla extract. Stir in semisweet chocolate and white chocolate chips and sliced brazil nuts. Spread mixture over the baked crust. Bake for 25 to 30 minutes longer, or until set and lightly browned. Cool in pan on rack. Cut into bars when completely cooled.