Had this on fish tacos but it would rock on sandwiches too.
1 large avocado
1/4 cup of sour cream
1/4 cup of mayo
Pit and cut the avocado into chunks I cut the avocado in half, then slice it inside the skin (without piercing the skin), then spoon out the sliced pieces into a medium bowl. Squeeze fresh lime over the slices. Add the mayo, sour cream and the remaining ingredients to taste. Blend together until creamy (I use a hand-held blender).