For Tortelloni: Cut 3-1/2-inch circles out of pasta sheets; discard trimmings. Place 1 Tbsp veal filling in center of each circle. Moisten edges with water, fold in half and pinch to seal. Moisten ends, overlap and pinch to seal.
Cook 6 tortelloni in boiling salted water 8 to 12 minutes or until al dente. Drain.
Sauté 3/4 cup mushrooms and 1 Tbsp parsley in 1 Tbsp oil until tender. Add 2/3 cup chicken stock; reduce slightly. Whisk in 1 Tbsp butter. Add 6 tortelloni; stir to coat. Serve immediately, with a drizzle of truffle oil, if desired.
Antico Posto, Oakbrook, IL, Executive Chef Russel Bry