I have been here 4 years and until a few weeks ago, didn't realize that I could make them at home, and with almost no effort. You can caramalize almonds and walnuts, as well, but the peanuts are most common.
Here is what you need: sugar, water, vanilla and peanuts. Not much, huh? I buy raw peanuts (mani crudo) from the local feria and roast them at 350°F (176°C) for about 15 minutes. Then I use them in the recipe for garrapiñadas, below.
1 Cup Water
2 Cups sugar
2 Cups roasted peanuts (300 grams or 11 ounces)
2 tsp vanilla
It couldn't be simpler. Mix water and sugar together in a large pan (I used an old frying pan, but make sure it is generous size), and mix over medium high heat until dissolved. Add peanuts and vanilla and you are on your way. Keep boiling and stirring constantly until the mixture begins to thicken.
Eventually (after about 10-12 minutes), it will produce a white foam. Then you can take it off the fire and stir vigorously, and the mixture will literally dry up before your eyes. The coating on the peanuts will be white and there will be sugar "dust" in the bottom of the pan.
Return to a lower flame and work the peanuts and sugar until it begins to caramelize. When they are a rich brown color (but not burnt), take them off the flame, turn them onto a non-stick surface and make sure they are separated. Voila! You have garrapiñadas.
I thought I should add this warning that a thoughtful reader passed on:
One must be EXTREMELY careful when working with candy made from caramelized sugar. Once the water boils out of the sugar, the temperature quickly goes WAY above 212 degrees, the boiling point of water. And sugar is like oil in that it holds much more heat than water. So sugar burns are much worse than burns from even boiling water. When sugar just BEGINS to turn golden, the temperature is around 350 degrees. So one must never even THINK of testing the temperature of melted sugar with a finger, or of licking the spoon!!
You may not live in a Spanish country, but you can enjoy garrapiñadas wherever you live.