Preheat oven to 220°C (convection oven) / 240°C (conventional oven). Pat the FETO dry with a paper towel and cut it into fine slices with a knife. Wash the potatoes thoroughly and slice them unpeeled into fine slices using a mandoline or a knife.
Wash the spinach, drain it, and place it in a pot or bowl. Pour boiling water over the spinach until just covered. Steep for two minutes, then drain and blanch. Stir in all of the ingredients except the herbs and red pepper, and spread out evenly on a baking sheet.
Bake until crisp. After 20 minutes, lower the temperature to 200°C and bake for another 5 - 10 minutes. Sprinkle chopped herbs and red pepper flakes over the baking sheet.
