Quinoa with sweet potatoes, red pepper and feta - chinese grandma

Ingredients

• 1 cup uncooked quinoa (about 2 1/2 cups cooked)
• 1 pound sweet potatoes
• 1 red pepper, diced
• 2-4 tablespoons minced onion or shallot
• 1/4-1/2 cup chopped flat-leaf parsley (or chives, basil, or mint)
• 1/3 cup crumbled feta
• Olive oil, salt and pepper for roasting sweet potatoes
• 2 tablespoons balsamic vinegar
• 3 tablespoons olive oil
• 3/4 teaspoon kosher salt (1/2 teaspoon table salt)
• 1/2 teaspoon black pepper