Put two large saucepans of water, each with a generous pinch of salt, on to boil for the potatoes and beans. Cut the new potatoes into quarters (no need to peel!) and pop them in one of your pans of boiling water. Cook for 12-17 mins. Tip: The potatoes are cooked when you can easily slip a knife through. Trim the tops from the green beans. Pick the tarragon leaves from their stalks and finely chop (discard the stalks).

Pat the tilapia dry with kitchen paper. Season the fish with a pinch of salt and black pepper. Put a splash of oil in a frying pan on medium-high heat. Once the pan is hot, add the fish, skin-side down. Fry for 4-5 mins. Then, carefully turn and cook for 2-3 mins more. Important: The fish is cooked when the centre is opaque. Remove it from the pan, set aside and cover with foil to keep warm. Keep the pan - we'll use it again!

While the fish cooks, pop the green beans in your second pan of boiling water. Cook for 4 mins, then drain in a colander and put to one side. Boil your kettle, then pour the boiling water (see ingredients for amount) into a measuring jug with the vegetable stock pot. Stir to dissolve, ready for the tarragon sauce.

Once the tilapia is out of your frying pan, add the stock to your pan on medium-high heat. Boil until it has reduced by one-third, 4-5 mins. Remove from the heat, then add the crème fraîche. Give it a good stir, then add the tarragon (don't use it all if you only want a subtle flavour). Taste for seasoning and add salt and pepper if necessary.

When the potatoes are cooked, drain in your colander and allow to steam-dry for 1 minute (you want as much water to drain out as possible). Return them to the pan and lightly crush with the back of a fork. For a decadent finish, toss them in a knob of butter (if you have some) and a pinch of salt and pepper.

Divide the crushed new potatoes and green beans between your plates. Top with the tilapia and finish with a generous amount of tarragon sauce. Enjoy!