As soon as the portobellos and peppers are cool, slice them in long, thick strips. Save the juices in the bowl. Make sure they are well seasoned. Lay nori, shiny side down on sushi mat and lightly pat on rice on bottom half of nori, 1/4-inch thick. Place mushrooms, peppers and scallions 2/3 up on rice. Roll, moisten end and let rest. In the bowl of juices, whisk in vinegar, mustard and shallots. Lift with oil, season, and check for flavor.
PLATING Slice the roll, both straight and on the bias. Drizzle with vinaigrette and serve immediately.
MASTER SUSHI RICE
Wash rice at least 3 times or until water is clear. Fill rice cooker or casserole with water to about 1-inch over rice. I highly recommend a rice cooker more than 2 billion people use them in Asia for a reason. Slowly heat vinegar, mirin and sugar until very hot but not boiling. Fold in su (vinegar and sugar) with the hot rice, add enough so that the rice has a tart/sweet taste. Rice should be shiny, not mushy. Carefully clean bowl with damp cloth, cover and let rest for 30 minutes.
Drink Suggestion: 3. Suishin, Japanese Sake 4. Laurent Perrier Champagne