Superb muffins using one of my favorite fruits this time of year when the rhubarb is plentiful. I especially like the crumb topping. :-) I should mention my muffins took a full 30 minutes to bake.
I used frozen rhubarb and it worked great! These are excellent muffins and I look forward to making them again. Next time I may add some nuts to the crumb topping, cause I love nuts in muffins!