1. Cut the avocados in half, remove the pit and scoop the flesh into the bowl of a food processor fitted with the steel blade. 2. Add the lime juice, sour cream, cream cheese and garlic and process until smooth. 3. Place in a bowl and season with salt. 4. Cover with plastic wrap, pressing wrap onto the surface of the dip. 5. Refrigerate at least 2 hours before serving, allowing the flavors to blend. 6. To serve, make a small well in the center of the dip and add salsa. Garnish with cilantro, if desired.