Yesterday I tried a new recipe for white truffle mac and cheese. Im
going to paste the recipe here but wanted to get thoughts on what went
wrong.

Once cooked, it was like a white sauce that broke with the oil
separating from the cheese.
Could it have been- cooked too long or at too high temp?
Could it have been the truffle oil?
I also added a bit more cheese than was called for when stirring the
cheese sauce but when I added it to the pasta it was very creamy. I
used really good cheeses so they would be a high quality. It tasted
WONDERFUL but looked not so nice.

Ideas?

8 oz (2 1/2 cups) uncooked mostaccioli or penne
2 tbsp margarine or butter
2 tbsp flour
1/4 tsp salt
1/8 tsp white pepper
Dash nutmeg
1 tsp white truffle oil
1 1/4 cups half-&-half
1/2 c shredded Fontina cheese
1/2 c shredded Gruyere cheese
1/2 c shredded aged White Cheddar cheese
2 tbsp dry white wine
2 tbsp sliced green onions

1. Heat over to 350. Spray 1 1/2 quart casserole with nonstick cooking
spray. Cook pasta to desired doneness as directed on package.
2. Meanwhile, in large saucepan, melt margarine over medium heat. Stir
in flour, salt, pepper and nutmeg; cook until bubbly, shirring
constantly. Gradually add half-&-half, stirring constantly. Cook until
mixture boils and thickens, stirring frequently. Remove from heat.
Stir in cheeses until melted. Stir in wine.
3. Drain pasta. Add to cheese sauce; stir gently to coat. Pour into
sprayed dish. Optional: sprinkle with onions.
4. Bake at 350 for 20-25 minutes or until edges are bubbly and mixture
is thoroughly heated.

Id love to make this again because it tasted so good so thanks in
advance for ideas!