I make Ina Garten's easy potato gratin for my family every Christmas, and it's the best holiday side dish

Garten's potato-fennel gratin requires just five main ingredients.

To make Garten's gratin for four, you'll need: 

• 1 pound russet potatoes (2 large ones)
• 1 small fennel bulb 
• ½ yellow onion
• 1½ cups Gruyère cheese 
• 1½ cups plus 1 tablespoon heavy cream

If you're trying to make the dish for a larger party, Garten also has a recipe that serves 10.

The first step is properly cutting the fennel.

I will admit that the first time I made this dish, I had to watch a Martha Stewart YouTube video on how to cut fennel, which I'd never cooked with before coming across Garten's recipe. 

But if you're an amateur, there's no need to let this herb intimidate you.

First, cut off the stalks by cutting as close to the bulb as possible. Then, cut the bulb in half lengthwise. 

Remove the cores at the bottom. For Garten's recipe, you'll then thinly slice the bulb halves crosswise — which should make approximately two cups of fennel. 

Pro tip: Don't throw out your stalks and fronds! Stewart recommends using the fronds in salads and saving the stalks for adding flavor to stockpot dishes. 

Once that's out of the way, get your onion ready.

You should thinly slice your yellow onion for this dish.

Peel your potatoes, then slice them crosswise.

Garten recommends thinly slicing them by hand or with a mandoline.

You'll also need to grate your Gruyère cheese

The total time it takes to prep Garten's gratin is under 10 minutes, which is great when you're juggling multiple dishes for a holiday feast. 

And don't forget to butter your baking dish!

If you're making the gratin for four, Garten recommends using a 9-by-9-by-2-inch baking dish. 

Once you're done with your prep, sauté your fennel and onions together.

Per Garten's recipe, you'll want to add 1 tablespoon of olive oil and 1/2 tablespoon of unsalted butter to a pan.

Then, sauté the fennel and onions on medium-low heat for 10 to 15 minutes, until they're tender. 

While your stove is working away, add your potatoes to a large bowl with the heavy cream.

You'll use 1 ½ cups of heavy cream for this step (the extra tablespoon is coming up in just a second). 

Then add 1 cup of the Gruyère cheese, as well as salt and pepper.

Garten recommends adding ½ teaspoon of salt and ¼ teaspoon of pepper to the mix. I really love pepper so, as you can see, I may have added a touch more.

Then add your sautéed fennel and onions on top.

It's almost time to bake!

To build the gratin, start by pouring your potato mixture into the baking dish.

Gently press down to smooth the potatoes out. 

Then mix the rest of your heavy cream and cheese together and sprinkle on top.

Remember, you'll want to use 1 tablespoon of cream and ½ cup of Gruyère for this quick step. 

After an hour in the oven at 350 degrees Fahrenheit, your gratin will be beautifully browned and bubbly — and almost ready to eat.

Garten recommends letting the gratin sit for 10 minutes before serving it hot. 

She also notes that the gratin can be cooked a day ahead and reheated at 350 degrees for 30 minutes, a helpful tip if you want to save some time on Thanksgiving or Christmas. 

Garten's potato-fennel gratin doesn't just look delicious — it tastes incredible too.

There are few things in this world more comforting than potatoes mixed with heavy cream and cheese. Garten's gratin is so creamy and satisfying thanks to the Gruyère, and the potatoes are perfectly cooked. And since the fennel is sautéed, its flavor is mild and sweet rather than overpowering. 

But one of the best things about the gratin is how well it goes with everything, making it a great sidekick for any meat or side dish.

I think the potato-fennel gratin is a perfect side for any holiday spread.

It's so simple to make, you could easily delegate the task to a young budding chef in your family, or at least let the kids help you with it in the kitchen. Plus, the gratin is easy to make ahead and reheat before dinner, giving you some much-needed space in the oven for a big holiday menu. 

And you can't go wrong with creamy potatoes and cheese, especially during the winter season. 

Believe me, you'll all be fighting for seconds.