Bring a large pot of
lightly salted water to a boil over high heat. Add the bow tie pasta,
and cook until al dente, 8 to 10 minutes. Drain and rinse well with cold
water, then toss with the olive oil, and set aside.
Stir the sour cream,
mayonnaise, lemon juice, lemon zest, dried dill, cayenne pepper, and
salt until smooth. Fold in the onion, peas, ham, Cheddar cheese, and bow
tie pasta. Garnish with the dill sprigs to serve.