Mojo de ajo, or "bath of slow-cooked garlic," is one of Mexico’s favorite dressings for seafood. Lime juice balances the richness of the garlic oil, and a touch of red chili adds a little awe.
The mojo de ajo keeps for a couple of weeks in the refrigerator (the oil will solidify but will liquefy again at room temperature), so I never recommend making a small amount. Mojo in the refrigerator represents great potential for a quick, wonderful meal. Warm the cold mojo slowly before using. For the best texture, cook the shrimp immediately before serving. Or cook them an hour or so ahead, douse them with the mojo and serve at room temperature.
For the mojo de ajo:
1/2 cup coarsely chopped garlic (about 2 large heads)
1 cup extra-virgin olive oil
1/2 tsp. salt, plus more, to taste
Juice of 1 lime
2 canned chipotle chilies en adobo, seeded and cut into thin strips
2 lb. medium-large shrimp, peeled and deveined
Salt, to taste
3 Tbs. chopped fresh cilantro or flat-leaf parsley
2 limes, cut into wedges
To make the mojo de ajo, in a small saucepan over medium-low heat, combine the garlic, olive oil and the 1/2 tsp. salt, stir to mix and cook, stirring occasionally, until the mixture is barely simmering. Reduce the heat to very low and cook at a very gentle simmer, stirring occasionally, until the garlic is lightly golden (the color of light brown sugar), about 30 minutes. (The slower the cooking, the sweeter the garlic.)
Add the lime juice and simmer, stirring, until most of the juice has evaporated or been absorbed into the garlic, about 5 minutes. Stir in the chilies, taste and adjust the seasonings with salt. Keep the pan over low heat so the garlic will be warm when the shrimp are ready.
In a large nonstick fry pan over medium-high heat, spoon 1 1/2 Tbs. of the oil (but not any garlic) from the mojo. Add half the shrimp to the pan, season with salt, and stir gently and continuously until the shrimp are just cooked through, 3 to 4 minutes. Stir in half the cilantro. Scoop the shrimp into a deep serving platter and repeat with another 1 1/2 Tbs. of the oil and the remaining shrimp and cilantro.
When all of the shrimp are cooked, use a slotted spoon to scoop out the warm bits of garlic and chilies from the mojo pan and scatter them over the shrimp. Serve immediately with the lime wedges alongside to squeeze over the shrimp. (You may have as much as 1/3 cup of the oil left over. Reserve for another use, such as sautéing just about anything.) Serves 6.