I have converted non-Brussel sprout eaters to lovers with this recipe. The creamy cheesy sauce is perfect with the slightly bitter sprouts, and the Dijon mustard adds an extra dimension. The best thing about this recipe is that what takes the longest is trimming and slicing the sprouts. This makes an excellent no-fuss side dish. Depending on the size of the Brussel sprouts, you may need more than a half a cup of cream to cover them completely. (This recipe was modified from one in Donna Hay Magazine.) —themodernapron
Combine cream, cheeses, and mustard. Taste and add salt and pepper as needed (because of the Parmesan, it may not need any salt, but a couple of grinds of pepper are recommended). You should have enough sauce to cover the sprouts completely. If not, add a bit more cream, up to 1 cup.
Place sprouts in a 4-cup capacity baking dish in a single layer. Spoon cream mixture over the sprouts, covering them evenly. The mixture is pretty thick, so you'll wind up sort of blopping it on and spreading it with the back of the spoon.