Banana Nut French Toast

INGREDIENTS

• 1 1/2 cups walnut halves
• 6 large eggs
• 1 1/2 cups heavy cream, half-and-half, or milk
• 2 tablespoons pure vanilla extract
• 1/2 teaspoon ground cinnamon
• Pinch of ground nutmeg
• Pinch of salt
• 6 ripe but firm bananas, peeled and cut into 1/4-inch rounds
• 1 1/2 cups packed dark-brown sugar
• 12 slices of bread, (1/2 inch thick), such as brioche or challah, preferably day old
• 8 tablespoons (1 stick) unsalted butter
• 4 tablespoons vegetable oil
• Pure maple syrup, for serving (optional)