Peel the potatoes, cook them in lightly salted water and let them steam off. Mash finely or press through a potato press and gradually stir in the other ingredients, finally the thyme leaves, with a whisk. If the mass is still too firm so that it is too difficult to stir, add some cream.
Season to taste with pepper, salt and a little lemon zest. Separate 1 tablespoon of the mixture, shape into small blinis and fry in a little melted butter over medium heat until golden.