In a skillet, brown the ground beef over medium heat until fully cooked.
Add taco seasoning and a splash of water; stir to combine.
Cook until the mixture thickens, about 5 minutes.
While the beef cooks, prepare the rice or quinoa according to package instructions.
In a large bowl, layer the cooked rice or quinoa as the base.
Add the seasoned beef on top of the rice.
Next, layer in the black beans and corn.
Add diced tomatoes and avocado for freshness.
Top with shredded lettuce and a dollop of sour cream.
Garnish with chopped cilantro and lime wedges on the side.