Clean and clean the mushrooms and cut them into slightly thicker slices. Heat the oil by the spoonful in a pan. Fry the mushrooms in it in portions until golden brown. Season with salt and pepper. Drain the mushrooms on kitchen paper.
Lightly roast the hazelnuts in a pan without fat. Remove, cool down a little and chop a little finer. Wash the chives, shake dry and cut into thin rolls. Stir butter until creamy, then add the nuts.
Halve the toastis and toast them. Spread with butter and cover with the mushroom slices. Season the toasties with salt and pepper, then sprinkle with chive rolls and diced ham. Garnish the toasties with chives.