Halve the avocados. Scoop out the flesh. Zest and juice the lemon. Peel, core and roughly chop the pears.
Put everything in a blender with the spinach.
Blitz and trickle in 250ml water or more till you reach your desired consistency.
If you're avocado is hard when you unpack it, pop it in a brown paper bag with the banana we've sent you and that will help ripen it up. You can also add the banana to the smoothie, although that will affect the calories and nutrition.