Remove the pits of the avocados, peel them very carefully or scoop them out with a spoon and place in a bowl. Mash the pieces with a fork but do leave a few whole. Sprinkle with lemon juice.
Blend the red onions in a blender.
Grate the garlic clove on a grater. Chop the jalapeno with a sharp knife. Add salt and freshly ground black pepper.
Notes: I used a jalapeno pepper. Keep in mind that it's really spicy, so be careful and add it to taste. It's not mandatory, you can substitute it with jalapeno powder - use about 1/2 tsp in that case.