Super simple, the best. I bet it was good.
It was excellent, and has long been a favourite of mine.
The classic (Italian) blue cheese sauce recipe usually calls for Gorgonzola (which is excellent, agreed), but I have found that any creamy - or soft - blue cheese works well, and I have also found that any combination of creamy (or soft) blue cheeses work exceptionally well with this dish.
Then, there is a classic "four cheese" sauce which is usually some combination of Gorgonzola, Taleggio, perhaps Ricotta, and definitely Parmigiano Reggiano.
However, I have learned that there are two or three tricks worth bearing in mind when preparing this dish: While this dish is prepared pretty quickly - it is, after all, one of the few genuinely 30 minute dishes (start to finish, completely homemade) in my cooking repertoire - the cheese sauce must be cooked on a low, surprisingly low, heat.
Dice the cheese, and melt it - slowly - on a low heat. Then, - the second thing, and the order is important - add the double cream, - thus, cheese first, followed by cream - still on a low heat, stirring all the while to break any lumps that may remain in the cheese. If you add the cream first, sometimes, the cheese will not melt fully into the cream and you will be left with lumps of cheese.
The third thing is to remember to add a few tablespoons of pasta cooking water to the sauce; this starchy liquid helps the pasta blend to the sauce, emulsifies the sauce still further, and it also adds a lovely flavour.
I usually serve either a green salad, or, steamed spinach or chard (steamed with a little butter and garlic) with this dish.