For some it might have been potato or green bean, but for me my gratin affinity began at an early age with macaroni and cheese. You know, the good old-fashioned kind with real cheddar and whole milk thickened with roux or egg yolks. The one that is baked until the correct ratio of crispy, crunchy top to creamy interior is achieved. It taught me early on in life just how fantastic a great food friendship is.

Then, as I came of age, somehow the gratin became any one-dish. It is tuna with the thin crispy onion rings baked on top or Chicken Divan with broccoli, cheddar, and crumbled Ritz crackers providing the crunch. There is the obligatory cottage pie, as done in the Midwest, topped with both cheddar and mozzarella, then browned. For a while, it was a multitude of eggy breakfast casseroles, all, of course, involving more cheddar.

It became neat, rectangular, and predictable. It served twelve. It was a 9×13 casserole world and I was living it.

I was fortunate. I got out. I went to college, I travelled, I ate.

With knowledge and experience came diversity. And we all know diversity makes the world a much better place. So I developed friendships with lasagna, cassoulet, moussaka, and the timballo, to name a few.

Through it all, and even though we didn’t see each other as much, the gratin remained my favorite.

What I realized is the gratin is the kick-ass cousin who went to college too. And when you reconnect at the family reunion you realize you hang with them because they are exciting, interesting, and you can rest assured that there is more depth to them than a spiky haircut and a couple of tattoos. You get each other in that way only family can.

I like the gratin’s quirks. I like its fondness for juxtaposition. I know that, without pretense, Tournedos Rossini can snuggle in next to a celery root gratin as easily as can Irish bangers and, regardless of which side of the tracks it finds itself, the gratin brings comfort to the table, weight to the unbearable lightness of being.

The thing is, the gratin comes by these traits naturally. But I also know that the things that make it stand out — the creamy interior and crunchy top — don’t just happen, that the building of flavors takes effort, and that without a true friend’s presence the gratin’s popularity might wane.

But then that is what true friends do, you know, bring out the best in each other, and relish in each others’ success.

Note: I have been making this recipe for years. It is based on a recipe in the Dean and DeLuca cookbook by David Rosengarten. I have always found it to be a lovely holiday side dish. It goes well with prime rib roasts and roast chicken. It is versatile and can be made ahead to be put into the oven when needed and also is easily doubled.

Serves 6 to 8

2 pounds russet potatoes, peeled and cut into 1/2 inch chunks

2 pounds celery root, peeled and cut into 1/2 inch chunks

Kosher salt and freshly ground white pepper

3/4 cups heavy cream

1 tablespoon garlic, minced

1/4 cup unsalted butter

1/8 teaspoon saffron, crushed

1 1/2 cup gruyere or comte cheese, grated

1. If you plan to cook the gratin right away heat the oven to 400 degrees. Otherwise move on to step two.

2. Place the potatoes and celery root into separate large pots. Cover by two inches with cold water and add a teaspoon of salt to each pot. Bring the pots to a boil over medium heat. Cook the vegetables until tender.

3. Once the vegetables are tender, pour them out into a colander set in the sink. Drain the vegetables and let them sit for a minute or two steam-drying.

4. Rinse out one of the pots and add the cream, garlic, butter, and saffron. Bring the cream to a boil over medium heat. Add a hefty pinch of salt and a few grinds of white pepper. Add 1/2 cup of the cheese. Stir it into the warm liquid till melted.

5. Place the celery root and potatoes into a mixing bowl (or the other blanching pot if it is big enough) and smash the mix with a potato masher. Add a pinch of salt then add the cream and saffron mix. Stir to combine. Taste and adjust the seasoning, adding more salt or pepper if necessary.

6. Use a little softened butter to grease an 8-inch oval gratin (12 inches long). Spread the rustic chunky mash out into the pan. Smooth the top with a spatula, then crosshatch the top with the tines of a fork. Spread the remaining cheese out over the top.

7. Bake until the cheese is browned, about 30 minutes. Let the gratin cool for 5 minutes, then serve.