Step 1Bring a large pot of water to a boil and salt generously. Fill a large bowl with cold water. Boil the fava beans until tender, about 8 minutes (10 if the beans are very large). Drain and transfer immediately to the cold water to stop the cooking process, then drain in a colander, ridding the beans of any excess water.
Step 2Fit a food mill with the fine blade. Puree the beans into a bowl.
Step 3Place the garlic cloves and salt into a large mortar and pestle and mash to a paste. Add the fava beans, along with the cumin, ¼ cup olive oil and the lemon juice and mash together until well combined. Taste and adjust the seasoning and flavoring if desired.
Step 4Serve the purée from the mortar, or mound onto a platter or in a wide bowl. Drizzle the remaining tablespoon oil over the top and garnish, if desired, with olives. Serve with warm triangles of pita bread.