1. THAW, RINSE AND DRY FISH. WRAP TORTILLAS IN FOIL AND PLACE IN 350 OVEN FOR 10-15 MIN.
2. MEANWHILE, FOR SAUCE, IN MEDIUM PAN COOK ONION,GARLIC,CORIANDER,AND PEPPER IN BUTTER TILL ONION IS TENDER. IN MEDIUM BOWL STIR FLOUR INTO SOUR CREAM. ADD BROTH, STIR TILL COMBINED. aDD SOUR CREAM MIX TO ONIONAND STIR IN JALAPENOS. COOK AND STIR OVER MEDIUM HEAT TILL MIX IS SLIGHTLY THICKENED AND BUBBLY. REMOVE FROM HEAT. ADD HALF OF THE CHEESE STIR TILL MELTED.
3. FOR FILLING, STIR 1/2 CUP SAUCE INTO FLAKED FISH. PLACE ABOUT 1/4 CUP OF THE FILLING ON EACH TORTILLA, ROLL UP. ARRANGE ON A LIGHTLY GREASED BAKING DISH WITH SEAM SIDE DOWN. TOP WITH REMAINDER OF SAUCE.
4. BAKE, COVERED 350 FOR 30-35 MIN. SPRINKLE W/ CHEESE. BAKE UNCOVERED FOR 5 MIN.