Asparagus, Lemon & Feta Soup

1. Peel and dice the onion. Trim the ends from the courgettes, then dice them. Snap the woody ends from the asparagus and set the tender tips to one side. Trim off any dry bits, then finely slice the woody asparagus stems.

2. Set a medium pan on a medium-low heat. Add 2 tbsp olive oil, the onion, courgettes and chopped asparagus stems. Season with salt and pepper and fry, stirring often, for 15 mins till the veg are tender. Don't let the veg brown too much. If they start to brown, add a few tbsp water to the pan and turn the heat down.

3. Half-fill and boil your kettle. Tip the vegetable stock powder into a heatproof jug. Pour in 1 ltr hot water and stir to dissolve the stock powder.

4. When the veg in the pan are soft, tip in the butter beans with the liquid from their tin. Add the asparagus tips. Pour in the vegetable stock. Turn the heat up and bring to the boil, then turn the heat down and simmer for 8-10 mins till the veg are soft.

5. Meanwhile, finely grate the zest from the lemon and halve it, ready for juicing.

6. When the veg are tender, ladle the soup into a blender and blitz till smooth. Pour back into the pan. No blander? Use a hand-held blender to blitz the soup together in the pan, or leave it chunky. Squeeze in the juice from half the lemon and stir to mix. Taste and add more salt, pepper or lemon juice if you think it needs it.

7. Ladle the soup into 4 warm bowls. Crumble the feta over the top and sprinkle over the lemon zest. Serve straight away.