If using vermicelli or thin spaghetti instead of orzo, you will need to break it off into tiny ½ inch long strands. A food processor works great for this because it chops it up in about 20 seconds.
In a medium pot, add the butter (or olive oil), vegetables, small pasta pieces, and rice.
Saute on medium high heat until pasta becomes toasted and browned.
Immediately add stock, vinegar, seasonings and herbs, and bring to a boil. Stir, lower heat, cover and steam on lowest setting for 20 minutes.
Remove lid, remove from heat, and fluff with a fork!