Originating in the Middle East, where it remains a popular aperitif, arak is an ancient spirit most commonly distilled from grapes and aniseed. In this hot-weather recipe from Arabic cooking experts Nadia Zerouali and Merijn Tol, the intense anise notes of arak and toum, an Arabic garlic sauce similar to aioli, make for an amazing summer snack when served over plump heirloom tomatoes.