Step 1

In a large bowl, combine the soy sauce, vinegar, brown sugar, and cornstarch until smooth

Step 2

Add the mushrooms and toss to coat

Step 3

Heat the vegetable oil in a large skillet over medium-high heat

Step 4

Once the oil is glistening, working in batches, use a slotted spoon to transfer the mushrooms to the skillet in a single layer

Step 5

Cook undisturbed, until golden and crispy on one side, about 4 minutes

Step 6

Stir and continue cooking until mushrooms have softened, about 3 minutes more

Step 7

Transfer the mushrooms to a plate

Step 8

Reserve leftover marinade

Step 9

Heat the sesame oil in the same skillet over medium heat

Step 10

Once the oil is glistening, add the bell peppers and cook, stirring, until beginning to soften, about 4 minutes

Step 11

Add the green onions, peanuts, ginger, garlic, and chili peppers; cook, stirring, until fragrant, about 2 minutes more

Step 12

Return the mushrooms to the skillet, add the remaining marinade and stir to combine

Step 13

Bring the sauce to a simmer, reduce the heat to medium-low and cook, stirring occasionally, until thickened, about 2-3 minutes

Step 14

Serve over rice if using.