Fill and boil your kettle, then fill a medium pan with the hot water, place on a high heat and bring to the boil. When the water is boiling, add the udon noodles and simmer for 8-10 mins till they're soft but still have a little bite. Drain and set aside.

While the noodles simmer, peel and finely slice the red onion. Halve the red pepper, scoop out the seeds and white pith, then finely slice the pepper. Trim the ends off the flat beans, then thinly slice them. Fill and boil the kettle again.

Warm a large pan on a medium-high heat. Add 1 tbsp oil, the onion, pepper and beans to the pan. Season with a pinch of salt and fry, stirring often, for 3-4 mins till the veg are just starting to soften.

Add 1 tbsp mild curry powder to the pan and stir to coat the veg. Pour in the coconut milk and 300ml hot water from the kettle. Simmer for 5 mins till the sauce has reduced slightly.

Drain the noodles if you haven't already, then divide them between 2 warm bowls.

Squeeze the juice from half the lime into the coconut curry sauce. Taste and add a pinch more salt if you think it needs it. Top the noodles with the curry, drizzling over a little sweet Thai sauce, and serve with wedges of the remaining lime half for squeezing.