In a large skillet, heat olive oil over medium heat. Add onion, green pepper, and mushrooms; cook for 4-5 mintues until soft. Remove from the skillet and set aside.
In the same skillet, cook the ground turkey until browned, about 7-8 minutes. Add salt and pepper. Mix in the pesto and sour cream (optional, but holds together more when you use it).
Cut bread loaves in half lengthwise. Brush with olive oil; sprinkle with garlic powder and toast/broil slightly.
Lay bottom of baguettes in a 9×13 pan. Place the ground turkey mixture on top, adding sices of mozarella cheese. Broil for 4-5 minutes until cheese is melted.
Place the other half of baguette on top. Cut into 2-3 inch sub sandwich pieces; serve right away!