In a large mixing bowl, combine the ground pork, fresh basil, minced garlic, chopped green onions, fish sauce, sriracha, sugar, cornstarch, black pepper, and kosher salt. Use your hands or a spatula to blend everything well until evenly mixed. Form the mixture into four patties.

In a separate bowl, whisk together the mayonnaise, sliced green onions, and sriracha until smooth and creamy. Taste and adjust the sriracha according to your desired spice level.

Heat a skillet over medium heat and add a drizzle of toasted sesame oil or regular oil. Once hot, place the patties in the skillet, allowing them to cook undisturbed for about 5 minutes on each side.

While the pork patties are cooking, lightly toast your brioche buns until golden brown. Once ready, spread a generous amount of the prepared sriracha mayo on the bottom half of each bun. Layer the bun with pickled vegetables, fresh cilantro, jalapeño slices if using, and the cooked pork patty. Top it off with the other half of the bun.