
Bring a large pot of generously salted water to a boil. Add the elbow macaroni and cook until al dente according to the package directions, then drain well.



While the pasta cooks, melt the butter in a large saucepan over medium heat. Stir in the flour and cook for 1 to 2 minutes, stirring constantly, until the mixture looks smooth and lightly foamy but not browned.



Slowly whisk in the heavy cream and milk, adding a little at a time so the sauce stays smooth. Bring the sauce just to a gentle boil, then reduce the heat to a simmer.



Stir in the mustard powder, onion powder, salt, black pepper, and hot sauce. Turn the heat to low, then add the shredded cheddar a handful at a time, stirring until melted before adding more.
Add the drained macaroni to the cheese sauce and stir until every piece is coated. Taste and adjust seasoning if needed, then serve warm.