Begin by assembling all your ingredients: fresh cilantro, limes, jalapeño, garlic, and mayonnaise. Rinse the cilantro thoroughly under cold water and pat it dry with paper towels. If you're sensitive to spice, carefully slice the jalapeño, remove the seeds, and set it aside for blending.

Using a citrus juicer, squeeze the juice from the limes into a measuring cup until you have about 2 tablespoons of juice ready for blending. Ensure to remove any seeds that might have fallen in while juicing.

In a high-speed blender, add the chopped cilantro, freshly squeezed lime juice, chopped jalapeño, minced garlic, and mayonnaise. Secure the lid tightly and blend on high speed for about 30 seconds until everything is smooth and creamy.

Check the consistency of your sauce. If it's too thick, add an extra splash of lime juice for a lighter texture and blend again for another 10 seconds.

Pour the sauce into a squeeze bottle or a glass container for easy serving. Refrigerate for at least 30 minutes to allow the flavors to meld.