Preheat the oven to 400°F and lightly grease a 9x13-inch casserole dish.
Add the rice, chicken broth, rice vinegar, and butter to the prepared dish.
Stir until well combined.
Arrange the broccolini over the rice, then place the pot stickers on top.
Cover the dish tightly with foil and bake for 50 minutes.
Check the rice for doneness before removing it from the oven.
If the rice needs additional time, cover and continue baking until tender.
While the casserole is baking, prepare the sauce by combining all of the sauce ingredients in a bowl.
In a separate bowl, whisk together the ingredients for the spicy mayo.
Once the rice is fully cooked, pour the sauce evenly over the casserole and drizzle with the spicy mayo.
For an optional finishing touch, sprinkle with sesame seeds before serving.