Place your roasting pan in the oven and heat to 400 degrees.

Take your Brussel sprouts, trim the ends and cut them in half, and place in a bowl. Season with olive oil, salt, and pepper and mix.
Carefully remove the roasting pan from the oven, add the Brussel sprouts cut side down, and place back in the oven to roast. This will take 30 to 40 minutes.

Meanwhile, place your hazelnuts in a small dry frying pan. Over medium-low heat toast your nuts being careful not to burn them. Remove from heat and allow to cool. Once they have cooled place the hazelnuts into a kitchen towel, and rub the towel over the nuts to release their skins. Remove the nuts from their skin and roughly chop. Set aside.

When the Brussel sprouts are done roasting place them into a serving bowl. Add the balsamic vinegar and balsamic glaze and combine. Top with the chopped hazelnuts and manchego and enjoy.