SCRUB, PEEL AND CUT THE POTATOES INTO CUBES.
ADD THE POTATOES TO A POT AND BRING TO A BOIL. BOIL 5-6 MINUTES.
ADD THE BUTTER TO A SAUTE PAN. AS SOON AS IT IS MELTED ADD THE ONION AND SAUTE 4-6 MINUTES. SPRINKLE THE FLOUR OVER THE ONIONS AND STIR UNTIL COATED.
POUR CHICKEN BROTH IN 1/4 CUP AT A TIME, STIRRING UNTIL INCORPORATED. SIMMER 3-4 MINUTES, UNTIL SLIGHTLY THICKENED.
REMOVE FROM THE HEAT AND STIR IN THE SOUR CREAM, SALT AND PEPPER.
ADD 2 CUPS OF CHEDDAR CHEESE AND STIR ONCE MORE.
TRANSFER TO A CASSEROLE DISH, ADD REMAINING CHEDDAR CHEESE AND COVER WITH FOIL. BAKE COVERED FOR 30 MINUTES THEN 15 MINUTES UNCOVERED.