To prepare the filling:
Heat butter in a heavy bottom pan. Add the flour/maida and mix with a whisk stirring continuously until smooth, about 2-3 minutes making sure there are no lumps formed.
Add the spring onion and greens and cook for 1-2 minutes.
Pour in the milk gradually stirring all the while until the sauce thickens.
When the sauce has thickened add the sweet corn kernels, tomatoes, salt, freshly ground black pepper and half the grated cheese and mix well.
Cook for 2-3 minutes.
To assemble the quesadillas:
Place a tortilla on a skillet/cast iron griddle on medium heat. Layer the sweet corn, shredded cabbage and some cheese onto the tortilla.
Top with another tortilla and let it cook for a couple minutes. Pour a few drops of olive oil and press down on the top tortilla with a spatula and then carefully flip the quesadilla.
Put some olive oil on the other side of the tortilla.
Cook for a couple more minutes, until the cheese is melted and the tortillas are crisped and slightly browned.
Serve with sour cream and mexican hot sauce.