Last night I whipped up another batch of my jalapeno mayonnaise. Boy is that good stuff, and really easy to make. I didn't take pictures so you'll just have to make do with old fashioned instructions.
First, acquire some jalapenos. How many depends on how much mayo you want and how spicy you want it. I used 5 medium sized peppers and made a pint of mayo, which ended up being on the mild side. Roast those puppies until their skins are all black and charred. You can do that over a gas stove or under the broiler. A trick to getting the skins off is to set the peppers on a plate and cover with a lid right after removing them from the heat. Water will condensate and the skins will slip off pretty easily.
Rough chop the peppers into smallish bits and toss into a blending machine. I've used blenders, I've used food processors, and I've done it by hand. Take your pick. Puree the peppers with a few tablespoons of mayo, just enough to give the mixture some bulk. Less blending equals a thicker sauce so adjust as you like.
Mix in enough mayonnaise to dilute to the correct taste. Store in a glass jar in the fridge for a month or so, maybe more. I've never done tests but I've never had any go to waste either.
One thing I'd like to try in the future is using homemade mayonnaise. It also is pretty easy to make and using different oils leaves open endless possibilities. I'm thinking mainly of trying some chili oil. Spicy.