Bring a large pot of heavily salted water to a rolling boil. Cook the pasta for about 7-9 minutes or until al dente. Drain and set aside.

In the same pot, melt the butter over low to medium-low heat, swirling occasionally for 1-2 minutes.

Whisk in the flour to create a roux, cooking for 1-2 minutes until it turns light golden.

Gradually add the milk while whisking until the sauce thickens and bubbles, about 2-3 minutes.

Reduce heat to low and stir in cheddar cheese, salt, and Greek yogurt until fully melted and smooth.

Fold the drained pasta into the cheese sauce until well-coated, then let sit for a minute.

Serve warm, optionally sprinkled with extra cheese or fresh herbs.