Earthy, sweet and satisfying, sweet potatoes would definitely be on my list of favourite vegetables (if I ever ran out of things to do and pulled such a list together).

Roasted (with a skewer through its heart to speed up the cooking) then mashed with lots of butter makes for a very comforting meal in its own right when I can’t be bothered to ‘cook’. The mash is also lovely combined with other chopped cooked vegetables (kale or cabbage are good), a sprinkling of cumin and lots of salt and pepper, and fried up into little sweet potato cakes. (Yotam Ottolenghi does a delicious version using chillli and a yoghurt dipping sauce).

Sweet potato can also be served for pudding. Dan Lepard introduced sweet potato into brownies as a means of creating a low-fat low-sugar version of a traditionally calorific treat. Weirdly, my Larousse Gastronomique proposes Sweet Potatoes A L’Imperiale - an intriguing gratin of sliced sweet potatoes, apples, bananas and a sprinkling of paprika - as an accompaniment to meat. My love for sweet potato may not stretch that far.

Japanese sweet potato

But as I’m researching Japanese food at the moment I thought I would try to create daigaku imo (translated as university sweet potato) - a candied sweet potato snack first popular among cash-poor students in Tokyo at the turn of the 20th century but now widely eaten as street food. It is a sweet-salty snack - more sweet than salty really - and not a meal in itself. To bulk mine out into a proper supper I cooked up some brown rice udon noodles to go alongside. These noodles have a distinctive, slightly fermented flavour and worked well with the sweet potato cooked this way. Ideally, white-fleshed Japanese sweet potato should be used for this dish - if you can locate it, soak it in water as soon as you have chopped it or it will go brown, then dry thoroughly with paper towel before frying. I could only find bog standard orange-fleshed version locally, and it worked fine.

Caramelized sweet potato with brown rice udon noodles

Serves 2

• 1 medium Japanese sweet potato (white flesh) scrubbed
• 1 teaspoon soy sauce
• 2 tablespoons granulated sugar
• 1 tablespoon glucose syrup or honey
• ground nut oil, for frying
• 2 tablespoons sesame oil
• 150g brown rice udon noodle, or any other Japanese noodle
• 1 tablespoon black sesame seeds
• Sea salt flakes (optional)

1. Cut the sweet potato with its skin on into 2cm dice.
2. Combine the soy, sugar and glucose or honey in a small saucepan and stir over a gentle heat until the sugar is dissolved and the mixture has reduced a little. Set aside.
3. Pour enough groundnut oil into a heavy-based pan to come 2cm up the sides, and then add the sesame oil. Heat until the oil reaches 170°C or a small piece of bread sizzles and goes brown in about 30 seconds.
4. Carefully fry the sweet potato and cook until crisp, golden and tender – about 5 minutes. You may need to keep adjusting your hob to prevent the oil getting too hot.
5. Cook the udon noodles in lightly salted boiling water for about 4 minutes, or until tender. Drain.
6. When cooked, remove the sweet potato from the pan with a slotted spoon to a serving bowl and pour over the soy mixture. Toss very gently to coat well.
7. Sprinkle over the sesame seeds. Depending on how salty your glaze is you may want to sprinkle over some sea salt flakes. Serve immediately with the noodles.