For the topping, heat EVOO and butter in a small pan over medium heat. Add garlic and stir 2-3 minutes then add panko and stir to combine and lightly toast, 1-2 minutes. Remove from heat and add in herbs and cheese.
For the onions, heat EVOO and butter in large skillet over medium heat. Add onions and bay, salt and pepper, and caramelize, 25-30 minutes. Deglaze with sherry or wine and add consomm. Keep warm over low heat.
Bring a pot of water to a boil for the pasta and preheat oven to 400F.
For the cheese sauce, melt butter in medium saucepot over medium to medium-high heat. Whisk in flour, cook for 1 minute then add milk. Season sauce with salt, pepper and nutmeg and thicken to coat spoon. Add Gruyre, stirring in figure-eight motion, and melt into sauce. Reduce heat to low.
Undercook pasta by a minute or so then drain and return to pot. Combine with onions and cheese sauce then transfer to a casserole dish. Top with breadcrumb mixture and bake until golden, 20-25 minutes. Serve with spinach salad or shaved raw asparagus salad alongside.