I tried Martha Stewart's and Ina Garten's baked mac and cheese recipes. The best added an unexpected ingredient.

Up first was Martha Stewart's creamy mac and cheese.

I started by melting a few tablespoons of unsalted butter in a pot on the stove.

I chose a midsize pot to make the cheese sauce in. 

While the butter was melting, I chopped some yellow onion.

The recipe calls for ¼ cup of diced yellow onion.

After the butter had melted, I added the yellow onion to the pot and stirred it. The smell of butter and onions quickly filled my kitchen.

The recipe says to sauté the onions until they become translucent, which should take about five minutes. 

While the onions were cooking, I set about the somewhat grueling task of grating all the cheeses.

Next, I cooked the macaroni noodles.

It took about five minutes to cook the noodles, since they're supposed to be a little undercooked before going in the oven. 

After the onions had become translucent, I added the flour.

It quickly thickened the onion-and-butter mixture. Per the recipe's instructions, I stirred the onions, flour, and butter together and left them for a few seconds until the mixture began to bubble in the pot.

I then added 3 cups of whole milk. The mixture was now starting to resemble a cheese sauce.

After a few minutes, the mixture had begun to thicken. 

To finish the sauce, I added the four types of cheese — fontina, Gruyère, cheddar, and Parmigiano-Reggiano — and seasonings.

After stirring the cheese sauce until all the ingredients were completely melted and combined, it was time to add it to the macaroni.

By the time I poured the noodles into the larger pot and added the cheese sauce, I had been prepping and cooking for about an hour.

However, the steps were easy to follow, and I was able to sit down once the mac and cheese was ready to be put in the oven.

You can make the mac and cheese in individual pans or in a larger 1 1/2-quart baking dish.

After scooping my mac and cheese out of the pot and into the dish, I realized I had a lot left over. I could have easily filled another dish. 

After 30 minutes in the oven, my mac and cheese was done.

Ina Garten's recipe for baked mac and cheese calls for fewer ingredients.

The recipe calls for a whopping 8 tablespoons of unsalted butter.

Two tablespoons are reserved for the end, so you start by melting 6 tablespoons in a pot on the stove. It's important to melt it at a low heat — you don't want the butter to burn or boil.

While the butter was melting, I started boiling the pasta.

The recipe calls for one pound of macaroni or cavatappi pasta. Garten also suggests adding a splash of oil to the boiling water to help keep the noodles from sticking together.

I then added the hot milk to the flour and butter mixture.

After adding the two kinds of cheese, my sauce began to thicken.

I seasoned the pot of cheese sauce with nutmeg, salt, and pepper. Ina Garten's recipe uses similar seasonings to Stewart's, except for the addition of cayenne pepper, which Stewart does not use.

Garten recommends boiling the noodles fully before putting them in the oven, rather than leaving them slightly al dente.

The cheese sauce in the Garten recipe was slightly thicker and had a distinct cheese pull.

I scooped the mixture into a baking dish and waited for the oven to finish pre-heating to 375 degrees Fahrenheit. 

Garten recommends topping the mac and cheese with breadcrumbs and tomato slices before putting it in the oven.

After about half an hour, the mac and cheese was bubbling, and the top was browned. The dish smelled heavenly.

The tomatoes were slightly roasted and blistered on the top.

I thought the tomatoes took this mac and cheese dish to the next level.