Make the toasted rice powder. Add uncooked rice to a dry skillet over medium heat.
Toast, stirring often, until golden and nutty, 8–10 minutes. If using kaffir lime leaves, toast them with the rice for the last couple of minutes. Cool, then grind to a coarse powder in a spice grinder or mortar and pestle.
You want a sandy texture, not dust.
Prep the aromatics. Thinly slice the shallot and chilies. Chop the herbs and green onions. Keep them separate so you can add them at the right time.
Cook the chicken gently. In a skillet, bring the broth or water to a simmer over medium heat.
Add the ground chicken, breaking it up with a spoon. Cook until just done and no pink remains, 4–6 minutes. Keep it juicy; don’t brown it.
Season while warm. Remove the pan from heat.
Stir in fish sauce, lime juice, and sugar. Taste and adjust: more lime for brightness, more fish sauce for saltiness, or a touch more sugar to round the edges.
Add heat and crunch. Fold in the sliced chilies and half the toasted rice powder. Toss to coat.
Add more rice powder to reach your preferred texture.
Finish with herbs. Let the mixture cool for a minute or two so the herbs don’t wilt. Add shallot, green onions, mint, cilantro, and Thai basil if using. Toss gently.
The herbs should stay fresh and vibrant.
Serve. Spoon into lettuce cups, or serve alongside warm jasmine or sticky rice. Add cucumber slices and extra herbs for crunch and freshness.