So I saw this done on Instagram last week. No measurements were given, it was merely described as the cook assembled it: maybe a pint of whole grape tomatoes and two rounds of Boursin cheese were put in a casserole dish large enough to become the final mixing bowl with some olive oil. I think, but am not positive, that garlic was added. The dish went into a hot oven for about 20 minutes, in which time the tomatoes burst. A fork was then used to roughly crush the tomatoes and cheese together. Hot pasta was added: mix mix, serve.
Cooking for two and concerned about fat, I personally thought two cheeses was big overkill and used only one (garlic and herb flavor, though the shallot/chive version would be as good). Additionally, I used a combination of fresh tomatoes on hand: 2 peeled romas (normally I consider tomato skin a good texture but the skins on these winter romas is very thick so I peeled them), a handful of yellow cherry tomatoes and some sugar-bomb grape tomatoes. I'd say I used 2 cups of tomatoes, 3 cloves of garlic and maybe 2 T olive oil. The whole cheese was then placed in the center and it went into a 400 degree oven, covered, for 20 minutes.
Not sure covering was necessary but I didn't want the cheese to form a crust, which it might have otherwise. And in fact, there's no reason why one couldn't do this on the stovetop. Meanwhile I cooked half a pound of spaghetti and chopped some parsley for color.
The ingredients are simple but the result is much more than the sum of the parts. We swooned over every bite. And yes, two cheeses would have been too much. Trader Joe's fermented black garlic bits sprinkled over the top was a great garnish.
Highly recommended!
Btw, locally, a single Boursin cheese runs about $9, but a trio of three is $10 at Costco.