For the onions:

1 1/2 cups white vinegar

1/2 cup sugar

2 bay leaves

2 cups water

2 medium red onions, thinly sliced into rings

1/2 cup Wondra flour (also called instant flour)

1 teaspoon ground dry mustard

1/2 teaspoon salt

1 cup vegetable oil

For the burgers:

1 1/2 pounds 85 percent lean ground beef

3/4 teaspoon ground black pepper

Vegetable oil

Salt, to taste

1/2 cup crumbled Stilton or Gorgonzola blue cheese

4 seeded hamburger buns

To prepare the french fried onions, in a medium saucepan combine the vinega...