If you do not have a fondue pot to prepare the fondue in, you may prepare a double boiler. To prepare a double boiler place 2 to 3 inches of water in a pot, and then place a heat-proof bowl over the pot. The bowl should make a tight seal. The heat should be turned up high enough to boil, then the temperature should be reduced to medium.
Place beer into the bowl with the garlic, dry mustard, horseradish, and Worcestershire sauce. Stir to combine. Combine the cheese and cornstarch together. When the beer warms to almost boiling add half of the cheese. Stirring the cheese constantly, until it has melted.
Continue to add cheese by small handfuls until all of the cheese has been melted completely. Add in 3 tablespoons of crispy cooked bacon. If you are using a double boiler remove from heat. Place the cheese in a bowl and garnish with the remaining bacon and sliced scallions. Serve with plenty of bread, baby-cut carrots, green apple, and other items of your choice.