Blend the egg yolks, salt and lemon until smooth. Add the oil whilst blending, then stir in the crushed Szechuan pepper. Season to taste with more salt and lemon juice if needed, then transfer to a piping bag.
Peel the onions and cut them in half; heat a frying pan and brown the onions on the cut side without oil. Bring the rest of the ingredients to the boil and leave the brine to cool.
Pour the brine over the onions and leave them to pickle for at least 2 days before use
Peel the pumpkin and cut it into slices about 1 cm thick. Heat some oil in a frying pan.
Add the pumpkin to the pan and fry over a high heat; when the pumpkin starts to brown, reduce the heat to medium. Add butter, garlic and thyme to the pan and let the butter sizzle; fry the pumpkin until it is dark golden and tender. Season with salt and pepper. Leave to cool on the kitchen worktop or serve warm
Kale: Bring 800 ml of water to the boil with butter, lemon juice and salt. Remove the stalks from the kale, tear it into bite-sized pieces and blanch them in the buttered water for 30 seconds. Remove them to a sieve and drain. Slice the shallot into thin rings.
Hay ash: Burn the hay in a clean pan outside, collect the remaining ash and place it in a sieve with a bowl underneath.
Spread a little mayonnaise on the rye bread and top with slices of pumpkin, followed by kale, pickled onions and almonds, then dot the rest of the mayonnaise around the top.
Finish with shallots and grate the cheese over the top; finally, sprinkle with hay ash and toasted almonds.
