Fill your kettle and boil it. Peel and finely chop the onion. Warm a large pan on a low heat for 2 mins, then add 1 tbsp olive oil and the onion. Cook for 8 mins, stirring often, till the onion is soft and lightly coloured.
Meanwhile, use kitchen scissors to snip the sun dried tomatoes into a large jug. Pour in 600ml hot water from the kettle and crumble in the stock cube. Stir and set to one side to infuse.
Trim the dry tips off the fennel, reserving any fronds for later. Chop the fennel into 1-2cm chunks. Finely chop the rosemary leaves. Pull 4 cloves from the garlic bulb (save the rest for your other soup recipe). Peel and grate 3 of the garlic cloves. Drain and rinse the butter beans.
When the onion has cooked for 8 mins, add the garlic, fennel and rosemary and cook for 3 mins, stirring every now and then. Add the butter beans and pour in the sun dried tomato infused stock. Pop on a lid and simmer for 10 mins.
While the soup simmers, peel and grate the remaining garlic clove into a bowl. Zest and juice in the lemon. Finely chop the parsley leaves and stalks and add them to the bowl. Pour in 2 tbsp olive oil and 1 tbsp cold water. Add a good pinch of salt and mix well. This is your gremolata.
Taste the soup and add more seasoning if needed – remember, the gremolata has lots of flavour so you may need less seasoning in the soup.
Leave the soup chunky, or blitz with a hand-held blender till smooth. Ladle the soup into warmed bowls and top with a generous spoonful of the gremolata to swirl through.