Place finely chopped shallot in a small bowl. Add the lime zest and juice, soy sauce, chicken broth, sriracha, worcestershire, and ginger. Stir and set aside.
Heat a large skillet or cast iron pan on the stove over medium heat. When hot, add the ground beef, seasoning with kosher salt. Spread the meat out and break into pieces as it begins to brown. Do not stir. Allow to begin to get brown on the bottom, about 4 to 5 minutes. As the bottom starts to get crispy, add the garlic, mushrooms and carrots to the skillet on top of the beef. Stir and cook a few minutes longer, until the beef is almost done and the vegetables are soft.
Add the shallot lime mixture to the skillet and cook, stirring constantly until the mixture has reduced and thickened slightly, a few minutes. Right before serving, throw in the chopped cilantro, drizzle with sesame oil, and stir well.
Serve the ground beef in the lettuce cups. Top with green onions, additional cilantro, hot sauce, and a bit of sour cream, if desired. Enjoy!