Place the ground beef, breadcrumbs, egg, garlic powder, Italian seasoning, and salt in a bowl. Mix with your hands until the ingredients are evenly combined.
Divide the mixture into 8 equal portions and roll each into a ball.
Heat a skillet over medium heat and add the meatballs. Cook for 10 minutes, turning them every few minutes until browned and cooked through.
While the meatballs cook, warm the marinara sauce in a small saucepan over low heat.
Split the brioche buns and place one slice of provolone on the bottom half of each bun.
Set a cooked meatball on the cheese, then spoon a tablespoon of warm marinara over each meatball.
Add the top bun and press two black olives into the marinara on each meatball to create eyes.