Preheat oven to 350 F. Line 9x13" pan with aluminum foil leaving it to exten 2" beyond the short ends of the pan. Grease the foil.
Melt the chocolates with the butter and cool. Beat the eggs, add sugars and beat. Add the chocolate to the sugar mixture. Add rest of ingredients and bake 30-35 minutes. Don't overbake. A cake tester in center of brownies should come out slightly moist. Allow the brownies to cool 45 minutes and then using the foil at ends as handles, remove from the pan and continue to cool. Make the glaze. Put the chocolate, butter and syrup in a sauce pan and cook until choco is melted. Meanwhile in a separate pan or microwave, bring the cream to a simmer. Add the cream to the chocolate mixture. Allow to cool in a separate container for 15 minutes. Frost the brownies and then put them in the refrigerator until the glaze has hardened.
I found they froze beautifully and in the interests of "my diet", I left out the nuts.These are about the best brownies I've ever made and they're nice and chewey.