Start the rice. If you are not using leftover rice, cook your rice according to the package directions. It usually takes about 15 to 20 minutes.
Prepare the sauce. In a small bowl, whisk together the soy sauce, brown sugar, minced garlic, grated ginger, and red pepper flakes if using.
Set it aside.
Cook the beef. Heat a large skillet or pan over medium high heat. Add the sesame oil. Once it is hot, add the ground beef.
Cook it, breaking it up with a spoon, until it is browned and fully cooked. This takes about 5 to 7 minutes.
Add the sauce. Pour the prepared soy sauce mixture over the browned beef. Stir well to coat.
Let it simmer for 1 to 2 minutes until the sauce thickens slightly and sticks to the meat.
Make the spicy mayo. In a small bowl, mix the mayonnaise with the gochujang (or Sriracha). Stir until it is smooth and evenly combined.
Assemble the bowls. Divide the cooked rice into serving bowls. Top with the seasoned ground beef.
Drizzle the spicy mayo over the top or serve it on the side.
Garnish and serve. Sprinkle with sesame seeds, sliced green onions, or your favorite raw veggies like cucumber slices or shredded carrots. Serve immediately.