In a 10-inch heavy saute pan, heat 1 ounce of clarified butter over high heat. Add sliced mushrooms one handful at a time to saute pan. As mushrooms begin to develop rich, brown color, push them to the outside of the saute pan. Turn the mushrooms over as they begin to color. When pan becomes dry, add remaining clarified butter to the pan. Add another handful of mushrooms to the pan and continue until all mushrooms have been added. Season with salt and pepper after the last addition to the pan has been made.
Make a hole in the middle of the pan and add the shallots. Deglaze pan with cognac, scraping up any browned mushroom bits. Add the chives. Adjust seasoning with salt and pepper.