INGREDIENTS
•
2 Tbs. unsalted butter, plus more for greasing
•
3 Tbs. grated Parmesan cheese
•
3 Tbs. all-purpose flour
•
1 cup (8 fl. oz./250 ml) whole milk, warmed
•
1 cup (4 oz./125 g) shredded Gruyère or Comté cheese
•
2 Tbs. chopped fresh chives
•
1/4 tsp. kosher salt
•
1/4 tsp. freshly ground pepper
•
4 large eggs, separated, plus 1 large egg white, at room temperature