Penne with Imitation Crab and Sherry Cream Sauce

I don't know that many people love imitation crabmeat, but in this house, we prefer it!  This recipe is an original.

2 TBSP unsalted butter
1/2 C minced onion
2 TBSP tomato paste
1/4 TSP red pepper flakes
1/2 C dry sherry
1 C skim milk
1 TBSP cornstarch (or flour)
2 TSP grated lemon zest
1 TBSP lemon juice from one lemon
1 box Ronzoni SmartTaste penne (14.5 oz)
1 LB imitation crabmeat, flaked
1/4 C finely chopped chives

Bring 4 quarts water to boil in a large pot.  Meanwhile, melt butter in a large skillet over med-high heat.  Add onions and cook until softened, about 2 minutes.  Add tomato paste and pepper flakes and cook until slighly darkened, about 2 minutes.  Stir in sherry and simmer until thickened, about 3 minutes.  In bowl, whisk together milk and cornstarch until smooth, then add to skillet with sherry.  Cook until thickened, about 3 minutes.  Off heat, add lemon juice and season with salt & pepper.

Add 1 TBSP salt and penne to boiling water and cook until al dente.  Reserve 1/2 C cooking water, drain pasta, and return to pot.  Add sauce, crabmeat, lemon zest, and chives and toss to combine, adding reserved pasta water as needed.  Season with salt and pepper.  Serve!