Bring a large pot of water to a boil, salt it, add the pasta and cook until al dente. Drain.
While the pasta is working, in a large skillet, heat a drizzle of EVOO over medium-high heat. Add the chorizo and cook until crisp, 2-3 minutes. Transfer to a paper towel-lined plate.
In a medium saucepan, melt the butter over medium heat. Add the shallots and garlic and cook until tender, about 5 minutes. Whisk in the flour, then whisk in the sherry. Stir in the chicken broth and milk and cook until thickened; season with pepper. Stir in the cheese. Fold in the peas and pimentos.
Drain the pasta, toss with the sauce and top with the chorizo and parsley.