Prepare the vegetables
Wash your hands with soap and water for at least 20 seconds and clean the preparation surfaces. Rinse the produce under running water, scrubbing the potatoes and trimming away damaged areas, then dry. Peel the potatoes and cut them into 1-inch chunks. Peel the onion, finely chop enough to measure 1/4 cup and thinly slice the remainder. Trim the mushroom stems and slice the mushrooms 1/4 inch thick.














