fried egg sandwich with bacon and blue cheese

INGREDIENTS

• 1/4 cup crumbled blue cheese
• 2 ciabatta rolls
• 1 1/2 cups frisée (French curly endive), torn into-bite size pieces (about 2 ounces)
• 1 bacon slice, preferably thick-cut
• 1 tablespoon minced shallot (from 1 small)
• 1 teaspoon smooth Dijon mustard
• 4 teaspoons red wine vinegar
• Salt and freshly ground black pepper
• 1 to 2 teaspoons unsalted butter, divided
• 2 large eggs