Preheat the oven to 200C (convection) oven
Prepare Brussels sprouts and cook in plenty of salted water for about 3 minutes.
Sieve and drain the Brussels sprouts.
In the meantime, core the pears and cut into cubes, approx. the size of your fingertip.
Mix the Brussels sprouts, pear cubes, mustard, vinegar and butter in a bowl.
Spread the Brussels sprouts mixture on a baking tray lined with baking paper.
Spread the coarsely chopped hazelnuts and the diced bacon evenly on the baking tray
Bake the Brussels sprouts in the middle of the oven for 35 minutes.
If necessary, season with salt and pepper