Slice Roma tomatoes vertically and place halves on an oven tray, lined with greaseproof paper. Sprinkle tomatoes with balsamic vinegar, sugar and pepper. Slowly oven-roast tomatoes for 1 hour until semi-dried. (If browning too much, turn oven down) *Note: This step can be done ahead of time.
Adjust oven temperature to 180°C (160°C fan forced).
Tear basil leaves and finely slice spring onions. In a large bowl, beat eggs and add, basil, spring onions, Vitasoy Soy Milky Lite, parmesan cheese, sifted GF plain flour and additional pepper. Stir until well combined.
Place Roma tomato halves neatly in a greased quiche or flan dish and gently pour egg mixture over tomatoes.
Bake for 50-60 minutes. Can be served hot or cold.