Tortilla chips - as an accompaniment.

In a bowl toss the cheeses with the flour and reserve the mixture. In a large heavy saucepan cook the onion in the butter over moderately low heat, stirring, until it is softened, add the beer, the tomatoes, and the jalapeno, and simmer the mixture for 5 minutes. Add the reserved cheese mixture by 1/2 cupfuls to the beer mixture, stirring after each addition until the cheeses are melted, serve the dip with the chips.

Makes 4 1/2 cups.