Bring a cup of water with a little salt to a boil. Stir in the rice and cook covered over low heat for about 20 minutes until al dente. Do not stir in between. Remove the lid and let it evaporate.
In the meantime, mix the crème fraîche with the lemon juice, the water, curry powder, sugar, salt and pepper in a small bowl.
Clean the spring onions and cut diagonally into 1/2 cm wide pieces. Peel the banana and cut it diagonally into thick slices. Quarter the zucchini lengthways, then cut into thin slices.
Heat a coated pan and let the fat melt in it. First fry the spring onions, then add the banana slices and fry until golden on both sides, season with salt and pepper. Add the zucchini slices and pour the curry sauce over them. Stir gently once and cook for about 1 minute. Remove from heat and cover and keep warm if the rice is not ready.