In a medium bowl, whisk together the eggs, whole milk, salt, and black pepper until well combined.
Heat olive oil in a large non-stick skillet over medium heat. Add the ground turkey sausage and cook, breaking it up with a spoon, until browned and cooked through, about 5 minutes. Remove the sausage from the skillet and set aside.
In the same skillet, pour in the egg mixture and cook, stirring gently, until the eggs are scrambled and just set, about 3-4 minutes. Remove from heat.
Lay out the flour tortillas on a clean surface. Evenly distribute the scrambled eggs and cooked turkey sausage over half of each tortilla.
Sprinkle the shredded cheddar cheese and Monterey Jack cheese evenly over the eggs and sausage.
Fold the tortillas in half to form quesadillas.
Heat the skillet over medium heat. Place one quesadilla in the skillet and cook for 2-3 minutes on each side, or until the tortilla is golden brown and the cheese is melted. Repeat with remaining quesadillas.
Allow the quesadillas to cool completely. Wrap each quesadilla tightly in plastic wrap and then in aluminum foil.
Place the wrapped quesadillas in a freezer-safe bag or container and freeze for up to 2 months.
To reheat, unwrap the quesadilla and microwave on high for 1-2 minutes or until heated through. Alternatively, reheat in a skillet over medium heat until warmed and crispy.