In several of Nigella's recipes she makes use of rhubarb. I grew up in the North of England, so we enjoyed rhubarb in crumbles, stewed, in pies and more. But my husband absolutely hates it. He won't eat it in anything, even if disguised within a fruit crumble or fool. Do you have any suggestions for a substitution veggie/fruit which may have similar texture or qualities?
Rhubarb is technically a vegetable and its main characteristic is that it is quite tart so generally it is cooked with plenty of sugar to help offset the tartness (though sometimes a less sweet puree is served with oily fish, such as mackerel). It also has a lovely pink colour, particularly the early, tender, forced rhubarb and the variety of rhubarb known as "champagne rhubarb".
If your husband doesn't like the texture of the rhubarb (it can sometimes be a little stringy) then try peeling the stalks with a potato peeler to remove some of the strings before cooking it to a puree. You can then pass the puree through a sieve or strainer to give a very smooth puree that can be used in fool or mousse.
Otherwise tart apples (such as Granny Smith's) combined with a red-coloured fruit would give you the sharpness and colour of rhubarb, though the texture will inevitably be different. For the red fruit we would suggest raspberries in the summer and cranberries in the winter. The fruit mixture will need to be cooked with sugar before eating and can be cooked to a smooth puree or left with a slightly chunkier texture.