Preheat a conventional oven to 350°F or a convection oven to 330°F. Line a 7" x 11" pan with aluminum foil, leaving a 2" overhang on the long sides, and butter the foil. Arrange the oven racks so one is in the center of the oven. Melt the unsweetened chocolate and the butter and stir with a whisk until smooth. Set the chocolate mixture aside to cool for 5 or 10 minutes. Beat the eggs, vanilla and sugar on medium-high speed for about 2 minutes until smooth and light colored. Scrape the bowl again and add the flour and chocolate chips, blending on low speed for about 20 seconds. Spread the mixture into the prepared pan and bake it in the preheated oven for 12 minutes. While the chocolate layer bakes, make the macaroon layer: Beat the egg whites and sugar at medium speed until foamy, about 1 minute. Add the nuts and chocolate chips and blend on low for 15 seconds. Scrape the bowl and add the flour, blending on low for about 20 seconds. Spread the mixture evenly over the chocolate layer. Bake for 15-18 minutes or until the macaroon layer just starts to feel firm to the touch. Do not over bake the bars; the macaroon layer will become firmer as it cools.
Make the ganache
Melt together the chocolate and cream and stir with a small whisk until smooth. Put the ganache into a pastry bag fitted with a 1/4" tube. When the brownie is completely cool, pipe a decorative pattern on the brownie between the macaroon rows. Store the bars in the refrigerator, well wrapped, for up to 5 days.
Chef's Note: With a chocolate base filled with chocolate chips, and a chocolate ganache topping, the chocoholics in your life will love this tasty bar. Hazelnuts and macaroons have a perfect affinity for one another, and the chewy macaroon layer is the perfect partner for the brownie base. Store it in the refrigerator if you choose to use the chocolate topping.