Prepare the ingredients as instructed above.

Prepare the cucumber water: Place the cucumber slices in a pitcher with water. Refrigerate to infuse. Serve over ice when ready.

Prepare French onion soup: In a heavy-bottomed pot, heat olive oil on medium. Add onions and cook, stirring often, until softened, about 10 minutes. Increase heat to medium-high, add butter, and cook for about 20 minutes, stirring frequently, until the onions begin to brown. Sprinkle sugar and salt, then continue cooking for about 10 more minutes until deeply caramelized. Add garlic and cook for 1 minute.

Deglaze the pot with Chardonnay wine, scraping up any browned bits. Add beef broth, bay leaf, thyme, and black pepper. Bring to a simmer, cover, and reduce to low for about 10 minutes. Taste, adjust salt and pepper as needed, and discard the bay leaf. Stir in brandy if using.

While the soup simmers, lightly toast the sourdough bread for the sandwiches. For the soup topping, brush the French bread slices with olive oil. Place on a sheet pan under a low broiler and toast until lightly browned, about 5–7 minutes. Turn slices, sprinkle with Gruyère and Parmesan, and broil until the cheese is melted, bubbly, and lightly browned.

Make the turkey and cheese sandwiches: Optional toast the bread. Layer with turkey, cheese, lettuce, and tomato.

Serve the French onion soup topped with the cheesy crostini alongside 1/2 turkey and cheese sandwich and cucumber water.