Place the jalapenos over open heat (grill, charcoal, broiler, gas stove top), turning occasionally until black and blistered on all sides.
Afterward, place the charred jalapenos in a bowl and wrap with plastic. Let them steam for about 10 minutes so that the skin loosens.
Then peel then the loosened skins either by hand of by using a paper towel.
Remove the seeds from the jalapenos but do not discard. Set aside.
Place the jalapeno flesh, mayo, sour cream, garlic, lime juice and a heavy pinch of salt in a blender or food processor. Blend until well combined.
Taste the dip and then add salt, pepper and reserved jalapeno seeds until the taste is to your liking. Can be eaten right away but it is best if made ahead of time.