I wouldn't have gotten through graduate school without this marinade recipe. It doesn't require special ingredients and cooks up quickly in the oven.
If you can't find fresh or frozen lemongrass or are feeling lazy, you can substitute it for 4 ounces of lemongrass paste. You can find it in a tube in the produce section of your grocery store, alongside the fresh herbs. Just make sure to omit the lemon juice, or else the mixture will be too wet.
Combine the chopped fresh or frozen lemongrass with the lemon or lime juice, diced shallots or onion, garlic cloves, fish or soy sauce, oil, and dried red pepper flakes to the bowl of a food processor, upright blender, or immersion blender. Pulse until the mixture is a thick smooth paste (about 5 minutes). Set aside.