Step 1 Place whole potato into a saucepan of cold water, cover, bring to the boil and simmer for 5 minutes. Drain under cold water.
Step 2 Meanwhile, combine zucchini, asparagus, 2 tablespoons sweet chilli sauce, dill, egg and flour in a bowl. Grate in the potato, season with pepper, then mix together. (The mixture may seem wet but will firm up in the pan.) Using floured hands, shape mixture into 8 flat patties about 1cm thick.
Step 3 Heat half the oil in a large frying pan. Fry half the patties for 8-10 minutes, turning once, until golden. Repeat with remaining oil and fritters.
Step 4 Combine sour cream, extra dill and remaining sweet chilli sauce. Serve with fritters.