Melt the butter in a pan and cook the onions over low heat until soft and translucent. Slice the zucchini and carrots into 1/4 inch thick slices. Add them to the pan, cover and cook for another 10 minutes or until tender. Season with salt and sprinkle with chopped dill. Meanwhile, beat the eggs with the flour. Stirr in the half and half, and add a pinch of salt.