Crustless Broccoli Quiche

Bahan-bahan (4 porsi)

• 2 tablespoons unsalted butter, (plus more for greasing the pan)
• ½ cup chopped shallots, (from about 2 shallots)
• 10 oz broccoli florets, (cut into 1-in (2.5-cm) pieces or smaller)
• 1 teaspoon salt, (divided)
• 6 large eggs
• 1¾ cups heavy cream
• Pinch ground nutmeg
• 1/8 teaspoon cayenne pepper
• 1½ cups (about 5 oz) shredded Gruyère