Not hummus, and it does not pretend to be. Hummus is smooth and this is not, because smooth needs a machine. What you get instead is coarse, nutty and a little rough, which on an oatcake is arguably the better texture anyway.
Keep the chickpea liquid. Drain them but save a few spoonfuls: it is starchy and it loosens the mash without thinning the flavour, which water does.
- Mash the drained chickpeas with a fork. Two minutes of real effort; you want most of them broken and a few left whole.
- Tahini, lemon juice, garlic granules, cumin and salt. Mash again.
- Trickle the oil in, stirring, then loosen with the reserved chickpea liquid a spoonful at a time until it drops from the spoon.
Tahini seizes when the acid hits it and looks wrong for about twenty seconds. Keep going: the liquid brings it back, the same way it does a seized chocolate sauce.
Serves 3 as a dip, 2 as a meal with crackers and gherkins.