First mince your garlic and chop your onion, and then set them aside.
Place a cast iron pan (or the pan of most convenience) on the stove over medium heat, letting it warm up while you get the ground meat from the fridge (or freezer; if frozen place it in a bowl of lukewarm water for 3-5 minutes).
While the meat lightly thaws (if needed) and the pan heats, roughly chop your Thai basil and lime leaves, and puree or microplane your ginger.
Once that's done, add one tablespoon of oil and wait ten seconds, then add the meat to your hot pan. Let it sit for about 30 seconds, cooking the bottom until it starts to come apart.
Break the meat up as much as you can, moving it around until it's covering as much of the bottom of the pan as possible. If there doesn't seem to be enough fat, add another tablespoon of oil to the mix, though the meat will release some fat. Stir for 3-5 minutes, until no longer pink and no longer sticking to the bottom of the pan.
Add the onion and turn the heat up to to medium-high, cooking the mixture and stirring occasionally for another 2-3 minutes. Meanwhile, gather the rest of your ingredients and finish any prep you haven't yet done. This is a good time to wash your lettuce leaves and divide them onto plates for serving.
Once the meat has all changed color and even started to brown, add the ginger, lemongrass, garlic, and chopped lime leaves. Cook the mixture for about 5 more minutes, until just lightly browned, stirring often.
Once the meat is done, turn off the heat but keep the pan on the hot burner. Immediately stir in the chopped basil leaves, fish sauce (if using), lime juice, and salt. If you didn't do it earlier, wash your lettuce leaves and stack them on each plate alongside the meat. Plate the mixture inside the lettuce leaves as you go, and enjoy!