Step 1Put the garlic cloves in a large steamer basket set over a pan of simmering water. Top with the spinach, parsley, celery and cilantro. Cover and steam until the garlic is soft and the greens tender, about 15 minutes. Cool, then squeeze the greens dry, finely chop and set aside. Mash the garlic cloves.
Step 2In a medium cazuela (earthenware pot) set over a flame-tamer or in a heavy-bottomed skillet, heat 1 tablespoon of the olive oil until shimmering. Add the garlic, olives, paprika, cayenne and cumin. Stir over medium high heat for 30 seconds. Add the greens and cook, mashing and stirring, until soft, dry and somewhat smooth, about 15 minutes.
Step 3Remove from heat and cool to room temperature. Add the remaining olive oil, mashing to combine. Refrigerate, tightly covered, for 1 to 4 days. To serve, return to room temperature. Stir in the lemon juice; season with salt and pepper. Serve with crackers or semolina bread.