Nopal is a species of the cactus family. Nopales (cactus paddles) are widely consumed in Mexico, their country of origin. They're at their best when the paddles have not matured too much, so their flesh is tender and the alguates (spines/thorns) are softer. They are low in calories yet rich in dietary fiber as well as a good source of B vitamins and minerals.
Rinse the paddles in cold running water, pat dry. Carefully, remove thorns and cut into strips.
In a saucepan, add the nopales, salt and cook until they release the gelatinous liquid (add some tomatillo husks to the nopales, as they are believed to help trap the gelatinous liquid). Do NOT add water.
When tender, rinse in cold water and set aside.
In a blender, put the tomatoes, onion, garlic, ají, culantro and vegetable broth. Blend until well combined.
Season the shrimp with salt, pepper and paprika.
In a large skillet, heat the oil over medium-high. Add the butter; wait until butter stops foaming.
Add the shrimp and cook until opaque and pink (3-4 minutes total). Remove from heat.
In the same skillet, add tomato mixture and cook for 4-5 minutes for a chunky sauce consistency. Adjust the seasoning.
Plate with some of the sofrito at the bottom, next the nopales and shrimps on top. Garnish with queso fresco.
Optional presentation: You can mix the shrimp and sofrito and serve over the nopales.