Sofrito, an aromatic sauce made using a mix of onion, herbs, and spices, acts as the foundation of umami flavor in these light and refreshing tacos. Serve with sliced radishes for a bit of crunch, and avocado for a dose of good-for-you fats, for a supremely well-balanced taco.
To make the sofrito, layer the onion, bell pepper, herbs, and garlic in a large blender or food processor. Blend until you have a uniform mixture.
Trim the tops off the sweet peppers, and add them to the food processor’s bowl. Pulse just until the peppers are finely chopped but still visible. Set aside.
In a large bowl, toss the shrimp to combine with the chili powder, coriander, lime zest, and salt. Warm the oil in a large skillet over medium-high heat; when it’s shimmering, carefully add the sofrito—it will give off a lot of steam—and stir for a minute or two, until some of the liquid cooks off and mixture begins to thicken. Stir in the shrimp (do this in batches if necessary), and cook for about 1 to 2 minutes per side, until they’re pink and firm. Remove the shrimp from the skillet, and roughly chop them; hold onto the sofrito left in the pan.
Toast the tortillas directly over a medium-high flame; when they’re slightly charred and blistered, flip and repeat. Fill each tortilla with shrimp and top with sorfito, avocado slices, and a handful of sliced radishes.