Prick the puff pastry with a fork and cook between two sheets of parchment paper and two baking trays in an oven at 200° for 10 minutes.
When the pastry is almost cooked, remove the paper and the top baking tray, brush with a little olive oil and sprinkle with some chillies.
Return the pastry to the oven without the covering for a further 10 minutes.
Cool flat and cut into 24 isosceles triangles 6 cm/12 cm.
Use a mandolin to slice the black radish into thin rounds.
Slice thin strips of rillettes from the shredded duck and place on 16 pastry triangles.
Top 8 of these with spinach leaves.Top the other 8 with a few rounds of black radish. Season the spinach and radish with a few drops of olive oil, vinegar glaze and ketchup.
Assemble the millefeuilles and cover with the last square.
Dip the caper berries in the tempura batter and fry at 180°.
Dry on a paper towel and season with salt.
Place on top of the millefeuille and garnish with spinach leaves, a few drops of ketchup and a sprinkling of Espelette pepper.
Serve immediately.