Peel and halve the potatoes and cook in a large pan of salted boiling water until soft, for approximately 20-25 minutes.
Preheat the oven to 220°C / Fan 200°C / Gas 7.
Drain and mash the potatoes and allow to cool slightly. Season and add the 60g of grated cheese and mix through.
Tear the Serrano ham into small pieces. Take a small ball of the potato mash and flatten into an oval shape in the palm of your hand. Place a small amount of the Serrano ham and a cube of cheese in the middle. Fold the mash into itself ensuring the ham and cheese are tucked inside. Repeat until you have formed all of the croquettes.
Place the flour, beaten egg and breadcrumbs each separate plates, or in shallow bowls. Mix the olive oil through the breadcrumbs (this ensures a nice golden finish to the croquettes that you would normally get from frying).
Take each croquette one at a time and roll in the flour, then the beaten egg and then coat in the breadcrumbs.
Place on a baking tray lined with parchment paper and spray with a light oil spray. Bake in the oven for approximately 20 minutes, turning half-way through, until golden.