Place olive oil, shallots, celery and prosciutto in a 12 to 14-inch
deep-sided frying pan and place over medium heat. Cook until soft but not
brown, 8 to 10 minutes. Add rice and stir over medium heat for 2 minutes,
until rice becomes almost opaque. Add chicken stock to
cover rice, turn heat up to high. As level of stock dips below level of
rice, continue to add stock, one ladle at a time, to keep rice covered.
Stir the rice constantly during this procedure. Taste the rice after 15
minutes: it should still be hard. Add peas and continue cooking, until rice
is soft and creamy, yet still al dente. Rice should still be quite wet, but
not swimming. Remove from heat and stir in butter and cheese. Adjust for
seasoning and serve immediately.
