Boil the elbow pasta according to the manufacturer's instructions. Drain and set aside. Be sure to salt the pasta water adequately.
8 ounces elbow pasta
I save at least ½ a cup of the pasta water. If you let your béchamel or the cheese sauce cook a little too long, the water evaporates, making the cheese sauce thicker than intended. The pasta water helps to thin the sauce while keeping it smooth.
Shred the white cheddar and fontina cheese and combine them by hand. Set aside.
10 ounces white cheddar cheese, 8 ounces fontina cheese
Make the Ritz Cracker Topping
Melt the butter in a pan over medium heat. Add the crushed Ritz crackers, stirring occasionally until evenly toasted (about 2 minutes).
42 grams Ritz crackers, 1 ounce unsalted butter
Set aside until ready to serve the mac and cheese.
Make the Truffle Mac and Cheese
Wipe the pan clean of any Ritz cracker bits, then melt the butter for the roux over medium heat.
1½ ounces unsalted butter
Add the all-purpose flour, whisking until it forms a smooth paste and is very light brown/beige in color.
½ ounce all-purpose flour
Slowly pour in the milk a little at a time to make a béchamel, continuously whisking until completely incorporated and the sauce is smooth.
12 ounces whole milk
Turn the heat all the way down to low and add half of the shredded cheese to the béchamel, along with the truffle zest and white pepper. Stir until the cheese has completely melted.
¾ teaspoons truffle zest, ½ teaspoon white pepper
Add the other half of the shredded cheese and stir again until the truffle cheese sauce is completely smooth.
Add the drained pasta set aside earlier and stir until all the pasta is coated.
Sprinkle the Ritz cracker topping on top of the truffle mac and cheese. Serve while warm (with shavings of fresh truffle and shredded Parmesan if using).
fresh truffle, Parmesan cheese
Store any leftovers in an airtight container in the refrigerator. Reheat easily in the microwave, stirring in increments so it heats evenly and retains its smooth texture.
Shred your cheese cold from the block. Cheese shreds more easily when it's cold, and pre-shredded cheese often doesn't melt smoothly due to anti-caking coatings.
Don't rinse the boiled pasta or add oil to the pasta water. The starchy coating helps the truffle cheese sauce cling to the pasta.
Keep the heat low when adding the cheese. High heat will make the white cheddar cheese sauce separate and get stringy.
If you need to make the mac and cheese a little in advance, keep it warm in the crockpot so the truffle cheese sauce stays smooth. Add the Ritz cracker topping right before serving.