1. Preheat oven to 275.
2. Toss the cherry tomatoes in the oil, balsamic, sugar and salt and pepper. Spread them out on a half sheet pan and place in 275 degree oven for about 45 minutes, stirring occasionally. After 45 minutes, remove from heat and smash tomatoes into a sauce, fold in the basil chiffonade and adjust salt and pepper. Set aside.
3. Increase oven temperature to 425. Grease a 9 x 12 Pyrex dish.
4. Over medium high heat, get a large cast iron skillet hot. Add oil and brown the diced onions, then add the pork sausage and brown, and crumble, about 5 - 7 minutes. With a slotted spoon remove onion/sausage mixture from pan and set aside.
5. Add some of the oil to the pre-used cast iron skillet, get it hot and then add the hash browns, spread them out, and let them sit. after about a minute, add more oil and salt and pepper.
6. When you see the edges starting to brown gently turn the hash browns over with a spatula, trying to not break up too much (you want hash browns that are crispy on the outside and tender in the middle-option...some people just like crispy hash browns in which case, do this in smaller batches, and get them all nice and crispy).
7. When all cooked through, remove from skillet and set aside. Wipe skillet clear and then add the butter, melt and then add the oven roasted ap flour (this is such a time saver when developing a dark roux-I prefer a roux on this to a bechamel because it has a much more developed flavor, but if you don't have the time, just add the flour and butter and cook down for about 5 minutes to cook out the flavor of the flour).
8. After about 5 minutes, carefully add the milk to blend...let this simmer for about 5 minutes, then blend in the 3 cups of shredded swiss, garlic, thyme and salt and pepper.
9. In the greased Pyrex dish, layer first ⅓ of the hash browns, then ⅓ of the cheese sauce and ⅓ of the cooked sausage, repeat 2 more times.
10. Bake the casserole in the oven for about 30 minutes, while the casserole is heating, poach the eggs. Remove the casserole after 30 minutes (tip: 45 min if you've refrigerated overnight) top with poached eggs and remaining 2 cups of swiss, return to oven for about 3-5 minutes to melt the cheese.
11. Top with melted tomatoes and serve.