Three apples blended with water and lemon, then strained. Five minutes, no cooking, and the lemon is there to stop it browning as much as for the taste.
Apple juice browns fast. The flesh oxidises the moment it is cut, and by the time it has been blended and strained it will already be turning beige, which is normal and not a fault. The lemon juice slows it considerably and is worth adding even if you do not want the flavour. Straining is what separates this from a smoothie: apple pulp is gritty rather than smooth. Leave the skins on for more colour and more flavour, since the sieve takes them out anyway.