Preheat the oven to 375ňöF.¬† Bring a big pot of salted water to a boil over high heat for the pasta.
Heat a 2-count of oil in a cast-iron or some other ovenproof skillet over medium heat until almost smoking.¬† Sprinkle the chicken breasts with a generous amount of salt and pepper and cook for 5 minutes, then flip the breasts and cook for 5 more minutes. Flip the breasts again, toss the pan in the oven and roast for about 25 minutes, or until the juices run clear when you stick a small knife into the chicken.¬† Meanwhile toss the plums in a bowl with a drizzle of the olive oil, salt, and pepper.¬† Throw them in with the chicken during the last 8 minutes of cooking.¬† Take the chicken and plums out of the pan, cool slightly, then stick them both in the refrigerator to chill.
Meanwhile, when the pasta water comes to a boil, add the penne and give it a stir to keep the penne from sticking together.¬† Boil 8 to 9 minutes until al dente. Drain in a colander and chill under cold, running water.¬† Drain again.
The last thing is to make the vinaigrette: Whisk together the mustard, vinegar, and sugar in a large serving bowl. Whisk in the oil and season with salt and pepper.¬† Fold in the herbs.¬† Slice the chilled chicken and toss into the bowl along with the pasta, the blue cheese, and the basil leaves. Toss, and taste for seasoning.¬†Mound on a plate with the plums alongside.
Edited: October 15th, 2009