Step 1

In a large saucepan, heat 2 tablespoons oil over medium. Add onions, fennel, thyme, and 1/4 teaspoon salt. Cook, stirring often, until brown, about 45 minutes. (If necessary, add a splash of water to keep onions from sticking.) Add sherry and Worcestershire; cook until evaporated, about 5 minutes. Let cool completely.

Step 2

Stir together labneh, garlic, and 1 teaspoon salt. Spread into a bowl or plate; top with onion mixture. Drizzle with remaining 1 tablespoon oil, sprinkle with more thyme, and serve with crackers and crudités.