Preheat the oven to 400 degrees. Line a baking sheet with aluminum foil.
Combine the chopped vegetables in a large bowl. Add the olive oil, salt, pepper, oregano, parsley, and garlic powder. Stir together until vegetables are well coated.
Spread the vegetables in a single layer on the prepared baking sheet.
Bake for 25 minutes, flipping halfway through.
While the vegetables are roasting, prepare the ground beef. Heat the oil in a large skillet over medium high heat. Add the ground beef and break it up into a few larger chunks. Leave it alone to brown for a few minutes, then use a wooden spoon to break it into smaller pieces. Continue to brown, stirring occasionally, until cooked through.
Stir in the garlic and cook until fragrant. Season with oregano, salt, and black pepper. Drain off most of the excess fat.
To serve, place about ½ cup of cooked rice in a bowl. Top with cooked ground beef and roasted vegetables. Garnish with your choice of tzatziki sauce, feta cheese and sliced banana peppers. Serve with pita bread wedges, if desired.