I love rhubarb and have recently devised a variation of a polenta cake that my family likes especially.
You could even serve it warm as a pudding with cream, custard or ice-cream - or even all 3!

8oz self raising flour
2oz polenta
4oz sugar (i tend to use castor)
5oz butter / margarine as you prefer
5 eggs
1tsp vanilla essence

8-12oz lightly poached rhubarb, drained (you could used tinned rhubarb well drained - ideally not too sweetened)
Demerara sugar or granulated to sprinkle on the top of your cake before cooking

Put all of the cake ingredients into a bowl and mix until a normal cake mix consistency is reached

Put half of the mixture into a 2lb bread tin or a deep 8-10" cake tin

Spread the drained rhubarb over the mix

Top with the remainder of the cake mix and sprinkle a little demerara or granulated sugar over the surface

The bread tin version takes about 40-45 mins at about 180C to cook, if the tin is shallower (such as the cake tin) it will take a little less.

You can test it by putting a skewer or similar into the top layer of cake and see whether it pulls out clean (cooked) or sticky (needs a little longer)