2) In medium bowl, mix the eggs, milk, paprika and salt and pepper. Add the chicken sausage and vegetable mixture and eggs together.
3) Heat a medium oven-safe saute pan over medium heat, add 1 tsp olive oil and pour in the egg mixture. Cook for 3 minutes on each side; the mixture should be slightly firm and moist.
4) In the meantime, add the tortillas to the oven and toast for 3 to 5 minutes until golden brown, then remove and keep warm.
5) Remove the frittata from the pan, place one tortilla on the bottom of the pan and spread with 1/2 of the cheese, place the cooked frittata on top, and top the frittata with the second tortilla. Top with the remaining cheese and place the pan in the oven for 5 minutes or until the cheese melts.
6) Remove from the oven and garnish with spring onions and tomatoes. Serve immediately.