Potato, Celeriac and Spinach Gratin

Potato, Celeriac and Spinach Gratin

2 c. milk
1/4 Red Dog Farm Yellow Onion, peeled, stuck with two cloves and a bay leaf
2 lbs Red Dog Farm Potatoes, peeled and sliced about a 1/4 in. thick
1 Red Dog Farm Celeriac peeled, halved top to bottom, then cut in 1/4 in. slices
4 T. butter
4 T. flour
A total of about 9 oz. of sharp & mild cheeses, grated
½ lb Spinach
2 T. Dijon mustard (or less, if you don’t like mustard)
1 tsp. paprika
a few chili flakes or ½ t. cayenne pepper

Preheat the oven to 375. Place the milk, onion, potatoes, and celeriac in a deep saucepan and bring to a gentle simmer. Simmer for 10 minutes, then remove from heat. Remove the potatoes with a slotted spoon and place in an 8×8 or slightly larger casserole dish. Season with salt and pepper. Remove the onion from the milk and reserve, but discard the attached seasonings. Chop the onion into long, thin slivers and set aside.

While the milk is simmering, prepare a roux using the butter and flour and cook over low heat for 5 minutes, stirring constantly. Set aside and allow to cool. Combine the warm milk and the cool roux in the large saucepan and place over low heat. Cook together until the milk thickens – do not allow to boil! Additionally, remember that the cheese will bind the sauce further, so don’t over-thicken it.

Rinse the spinach and put in a pan to steam with the water still on the leaves. Cook gently until softened, then chop roughly.

When the sauce has thickened, add the grated cheese and stir occasionally until incorporated. Again, do not allow to boil. Taste for seasoning and add the slivered onions, salt and pepper if needed, and the spinach and stir until combined. Pour over the potatoes in the casserole and mix in gently. Bake for 35-40 minutes or until the top is slightly browned and the dish is bubbling. Makes 4 large servings.