Barefoot Contessa | Potato-Fennel Gratin (updated) | Recipes

Ingredients

• 2 fennel bulbs, stalks removed
• 1 yellow onion, halved and thinly sliced crosswise
• 2 tablespoons good olive oil
• 1 tablespoon unsalted butter
• 2 pounds russet potatoes, peeled (4 large potatoes)
• 2 cups plus 2 tablespoons heavy cream, divided
• 2 ½ cups grated Gruyère cheese, divided (½ pound)
• Kosher salt and freshly ground black pepper