Take a pan of water and add salt until it comes to a boil, and cook the pasta in it.
While the water is on a boil, in another pan, heat the butter and add mustard, salt, nutmeg, pepper, and flour. Keep stirring it to ensure that a roux is created and the flour is properly cooked.
Slowly put the almond milk into the mixture you prepared and cook for a few more minutes while constantly whisking it. Finally, add in the cheese and turn off the stove.
In the pan where you have prepared the sauce, add the drained pasta and mix it again.