Sauce: Place water and cornflour OR rice powder into a small bowl. Mix into a slurry. Add lime juice, fish sauce and sugar and mix to combine. Set aside.
Heat peanut oil in a wok (or heavy based fry pan) over medium high heat. Add ginger, garlic, lemongrass and chilli and sauté for 45 seconds to 1 minute until fragrant. Do not let the garlic burn, it will taste bitter.
Add the chicken and turn up the heat to high. Cook the chicken, breaking up the mince into small pieces.
Once the chicken turns white and is almost cooked through (about 3 to 4 minutes), add Sauce. Cook for 45 seconds to 1 minute to coat the chicken and for the sauce to thicken.
Remove wok from heat. Stir through onion, coriander/cilantro and mint.
Spoon filling into a bowl, and serve with lettuce, peanuts, extra herbs and lime wedges on the side - leave everyone to make their own. Spoon filling into lettuce cups and garnish with what you want!
Sauce option: Take it over the top by serving with Thai Peanut Satay Sauce, as pictured in the first photo in post! It's extra amazing (though not traditional!)