4 ounces cream cheese, softened at room temperature
1/2 teaspoon cayenne
Make the brats: In a large saucepan, boil sausages in beer for 20 minutes until cooked through.
Preheat the oven to 400 degrees.
Line a baking sheet with parchment paper and lay out puff pastry. Spread mustard evenly across the puff pastry dough. Roll each brat up and slice into one-inch pieces. Place pieces on lined baking sheet and brush with egg wash. Bake for 20 to 25 minutes until golden.
Make the fondue: In a medium saucepan, combine beer and lemon juice and bring to a boil. In a large bowl, toss shredded cheeses with cornstarch, and stir into beer mixture. Add cream cheese and cayenne and whisk until smooth. Fondue is best kept in a slow cooker for up to 2 hours.