Preheat oven to 375 degrees F. Add tomatoes to a nonstick baking sheet and toss with salt, pepper and olive oil. Roast for 20 minutes, until the tomatoes are slightly bursting – yes, they will sort of burst even though they are cut in half. Once finished, remove and set aside until ready to use. I found it was easiest to “divide” them (with a spatula) into three equal portions on the baking sheet.
While tomatoes are roasting, prepare water for the lasagna noodles and boil according to directions – only halfway since they will cook in the oven.
Heat a saucepan over medium-high heat and add butter. Whisk in flour to create a roux, cooking for 1-2 minutes until golden. Add in milk and stir constantly until slightly thickened, then reduce heat to medium-low and add mascarpone, garlic, mozzarella and provolone. Continue to stir until cheese sauce is creamy and melty. Add in oregano, thyme, salt and pepper.
To assemble lasagna, place three noodles on the bottom of a 9×13 baking dish. Cover in roasted tomatoes, a handful of basil, a handful of fontina cheese, then a few ladles of cheese sauce. Layer three more lasagna noodles on top. Repeat this two more times, finishing with four lasagna noodles on top. Cover those with remaining fontina and any extra cheese if it looks like it needs it. Ladle any extra sauce on top. Bake for 35-40 minutes, until cheese on top is golden and bubbly. Let cool for 15 minutes before serving, so lasagna can kind of hold together.