Cook pasta according to package instructions and set aside to cool. In saucepan, melt Kerrygold Pure Irish Butter over medium heat, add onion and lightly season with salt. Add a pinch of sugar and cook onion until translucent.
Add flour and cook 2 to 3 minutes, stirring constantly. Do not cook long enough to color. Whisk in milk and cream and incorporate totally. Bring mixture to a simmer; add bay leaf and cloves.
Reduce burner to low heat. Cook for 25 minutes, stirring occasionally. Turn off heat and remove bay leaf. Whisk in 1 cup each of the Kerrygold Cheddar and Swiss Cheeses, until incorporated. Season with salt, pepper and nutmeg. In large bowl, combine pasta and cheese sauce. Spoon into 2 ½-quart casserole dish. Combine remaining cheese. Top with grated Dubliner®, thyme or other chopped herb, and a small handful of breadcrumbs. Bake at 375° F for 8 to 10 minutes.
For an added touch of hearty goodness, add ¼ cup of cooked and chopped bacon or French ham or 1 ½ cups of wild mushrooms sautéed in olive oil with chopped shallots and garlic. Adding chopped parsley or another favorite herb is also an easy and tasty option.