I have a good Peruvian restaurant (Pio Pio) in my neighborhood and they have a great green sauce. I've asked the waiters about the ingredients and recreated an aji sauce at home. I'm not sure how the Aji sauce at Mario's tastes like, but the one I've made is pretty good. I also have a recipe post on my blog for Peruvian roast chicken.
For the Aji sauce, puree these ingredients together:
2 jalapeños, de-seeded
1 cup cilantro, packed
1 garlic clove, chopped
1/2 teaspoon lime juice
1/2 cup mayonnaise
1 teaspoon white vinegar
2 tablespoons parmesan cheese, optional
Limonay, immense thanks for the recipe! Out of curiosity, is the restaurant you mentioned this one?:
Mario's is my favorite Peruvian restaurant, I've been going there over 20 years, and their Aji is the best I've ever tried. I hope that you get a chance to try their food. I will try your recipe out!