Halve the avocadoes, remove the pits and scoop out the flesh.
Chop flesh roughly and place in a food processor.
Add the onion, the lime juice, the sour cream, a few drops of Tabasco, season with salt and pepper and puree on high until smooth.
Taste for seasoning.
If not using right away store in an airtight container with a layer of plastic film stuck to the surface of the guacamole to prevent the air oxidizing the surface.
Dollop on top of grilled fish or chicken with a little chopped tomato flesh and fresh coriander (cilantro), or serve with freshly steamed vegetables, chilli con carne, rice and of course corn chips and salsa.