Using a sharp knife, scratch the skin of the duck breast in a diamond shape.
Season the meat all around with salt and pepper.
Heat the rapeseed oil in a pan and press the garlic cloves with the back of a knife.
Put the duck breast with the thyme sprigs and the garlic in the pan and fry until crispy on the skin side.
Cook in the oven at 135 ° (top / bottom heat) for about 14 minutes and then leave to rest for 5 minutes.
Peel the potatoes and cut into small cubes.
Peel the shallots.
Wash the kale, remove the stems and roughly chop the leaves.
Heat the butter and olive oil in a pan over medium heat.
Add the potato cubes, season with salt, pepper and fry for about 15 minutes, stirring occasionally.
Add shallots, fry for another 5 minutes until they soften and the potatoes turn golden brown.
Increase the temperature, add the kale and fry for another 3 minutes until it is crispy around the edges.
Cut the duck breasts into even slices and serve decoratively with the roasted vegetables on preheated plates.