As you may have already deduced, I have a rather enthusiastic love for sweet potatoes, cheese, and smokiness. So, I decided to pull everything together (once again…) into a delicious Smokey Sweet Potato Gratin. Yum.

It’s very simple—layered slices of sweet potatoes, sprinkled with goat cheese and covered in a smokey, mustard spiked, black-pepper laced cheese sauce. Baked for an hour, its soft and creamy, with a rich, brown crust.

It’s wonderful with a simple salad of arugula, toasted nuts, and goats cheese, with a drizzle of nice olive oil (pomace) (USA / Canada). It’s also nice on its own if you’re feeling lazy, which I’ve definitely been known to do.

This is how thick the flour/butter paste should be before you start adding the milk.

Smokey Sweet Potato Gratin

1 sweet potato, halved crosswise & lengthwise, and sliced into 5mm wide slices
½ cup crumbled goat cheese

¼ cup butter
¼ cup all purpose flour (more as needed)
1½ cups milk, warmed (more or less as needed)
1 cup shredded smoked cheddar cheese
½ tsp mustard powder
Pinch of cayenne
¼ tsp freshly ground black pepper
Salt, to taste

Grease a 9×12″ casserole dish and preheat your oven to 350°F.

Layer the slices of sweet potato in the casserole dish as shown, on an angle. Add a bit of crumbled goats cheese between the layers as you go, and then sprinkle the rest on top.

Now to make the cheese sauce. Melt the flour in a saucepan over medium heat, and then slowly stir in the flour. You’re looking to make a thick paste, as shown in one of the above photos.

Once you’ve got a nice, thick paste (a roux), cook it for a few minutes, stirring, to ensure there’s no raw flour flavour. It will brown a bit.

Once your roux is golden, add a bit of milk. The mixture will immediately thicken into a super thick paste—don’t worry, that’s normal. Slowly add milk, little by little, stirring and cooking as you go. The slow additions are very important—if you add it all at once, you will just have a lot of milk with little greasy lumps of flour floating around in it.

Once you’ve added enough milk to have a sauce that’s about the consistency of heavy cream, add the shredded smoked cheddar, mustard powder, cayenne, and black pepper. Stir until the cheese has melted, and taste. Season with additional mustard, cayenne, salt, and pepper as needed.

Cook until the sauce has thickened a bit (but not too much as it will reduce in the oven) before pouring it over the layered sweet potatoes.

Bake in the pre-heated oven, covered for 30 minutes, and then uncovered for another 30, until the sweet potatoes are tender and the cheese sauce has browned and is bubbling.