Combine the pasta, water, milk, Dijon, sea salt and garlic powder in a large stockpot. Heat over medium-high heat, stirring the pasta once every few minutes, until the water reaches a boil. Adjust heat as needed to maintain a rolling boil. Continue cooking the pasta, stirring once or twice per minute, until the pasta is *just* barely al dente. (Cooking time will depend on the shape of pasta that you use, so please keep a close eye on it.) Remove pot from heat.
Check to see how much starchy pasta water remains in the pot. If it seems that there is more than 1/2 cup or so, dip a heatproof measuring cup in to remove and save the excess water, then set it to the side. (If by chance there is no starchy pasta water left, please add 1/2 cup hot water to the pot.)
Add the cheese to the pasta and gently stir until completely melted. If the pasta seems too dry, stir some of the reserved starchy pasta water back in as needed.
Taste and season with additional salt if needed.
Serve. Serve warm, garnished with a few twists of black pepper and enjoy!