Line 2 baking sheets with waxed paper; set aside. Line 2 additional baking sheets or 1 tray with paper towels; set aside.

Place 1 1/2 cups of flour in a shallow bowl. Pour the milk into a second shallow bowl. In a third bowl, stir together the cornmeal, 2 cups flour, sugar, salt, paprika, cayenne pepper, thyme, and black pepper.

Dip the onion rings first into the plain flour, then into the milk, and last into the cornmeal mixture. Place the breaded rings on the wax paper-lined baking sheets.

Heat the oil in a large heavy skillet over medium-high heat, or deep-fryer to 365 degrees F (185 degrees C).

Fry the onion rings a few at a time in the hot oil so they are not crowded, until golden brown. Drain on paper towel-lined baking sheets, and serve immediately.