Spicy Mushroom Larb

Name: Spicy Mushroom Larb
Ingredients: 6 Tbsp. vegetable oil, divided; 1½ lb. shiitake mushrooms, stems removed, caps quartered; 6 scallions, thinly sliced; 4 garlic cloves, finely grated; 1 (2-inch) piece ginger, peeled, finely grated; Kosher salt; 2 medium shallots, thinly sliced, rinsed; 2 red chiles (such as Holland, Fresno, or Thai), thinly sliced; 2 cups mint leaves, torn if large; 2 Tbsp. fish sauce; ½ cup coarsely chopped unsalted dry-roasted peanuts, divided; ½ head of green cabbage, halved crosswise, leaves separated