Start the onions first. Melt the butter with the oil in a wide pan, add the onions with a big pinch of salt and cook over a low heat for 40-45 minutes, stirring every few minutes. Low and slow is the whole point: rushed onions taste of nothing.

Finish them. Add the sugar and balsamic, turn the heat up and cook for 3-4 minutes more until sticky and deep mahogany. Season and cool to room temperature.

Crisp the crumb. Blitz the sourdough to a coarse rubble. Fry in the butter and oil over a medium heat for 6-8 minutes, stirring often, until golden and properly crunchy. Stir through the thyme and salt and drain on kitchen paper.

Whip it. Beat the cream cheese smooth, then fold in the creme fraiche, horseradish, mustard and lemon. It should hold a soft peak. Taste and push the horseradish harder than feels sensible, because the beef and onions are both sweet.

Build in the ring. Set a 9cm ring mould on each plate. Press in a 1cm layer of crumb, then a layer of caramelised onions, then the horseradish cream, smoothing the top flat. Chill for 20 minutes so the layers set enough to hold.

Add the beef. Lift the ring away slowly. Drape the sliced beef loosely over the top in folds rather than flat sheets, so it catches the light.

Dress it. Spoon the warm jus around the base and let a little run down the side. Finish with watercress, micro herbs, flowers, a parmesan tuile pushed in at an angle and plenty of black pepper.

Serve straight away, while the crumb is still crisp and the beef is at room temperature.