In a large bowl, whisk together the oil, yogurt, Worcestershire, garlic, and salt and pepper, to taste. I use about a half teaspoon of salt and a few grinds of the pepper mill.
Stir in the blue cheese and chives, then add a little buttermilk to reach your preferred consistency. Three tablespoons of buttermilk creates a a consistency I like for dressing. You may want it just slightly thinner for using as pasta sauce.
Cover and refrigerate at least 1 hour before serving.
Cook the pasta according to the package directions. Drain and return to pot.
Pour in the dressing and the peas and cook over low heat until the peas are warmed and the cheese is melted.
Sprinkle with chopped chives, if desired.