Step 1

1 Position a rack in the center of the oven and preheat to 400 degrees

Step 2

2 Line a large, rimmed baking sheet with aluminum foil, and lightly grease the foil with vegetable oil

Step 3

3 In a large bowl, toss together the mushrooms, shallot, garlic, lime leaves, if using, and lemongrass, if using

Step 4

4 Add the vegetable oil and fish sauce and toss thoroughly to coat

Step 5

5 Spread the mushrooms in an even layer on the baking sheet – it’s fine if they overlap – and roast for 20 minutes

Step 6

6 Using a spatula or tongs, toss the mushrooms lightly and roast for another 10 to 15 minutes, or until the mushrooms are well browned and crisp

Step 7

7 Make the sauce: Meanwhile, in a small bowl, mix together the lime zest, juice, brown sugar, fish sauce and chile-garlic sauce

Step 8

8 Serve the mushrooms and sauce family-style, with lettuce leaves for scooping and stuffing and herbs and sauce for sprinkling and drizzling on the side