1. Cook the potatoes in lightly salted boiling water until tender. Leave to cool and then put through a ricer to make a fine texture.
2. Heat the butter in a skillet and lightly fry the garlic with the mustard. Add the cream and heat just until warm. Stir into potatoes to make a smooth mashed potato.
3. Stir in the blue cheese, 50 grams of the panko crumbs and spinach.
4. Portion the mixture into golf-sized balls. Chill for easier handling if you need to.
5. Toss the balls in the flour, then dip in the egg. Roll in the panko. Then deep fry.
6. Season with salt and serve warm.