Everybody knows rhubarb’s best friend is strawberry, but I think raspberry deserves a chance. Enter these raspberry-rhubarb muffins. They’re tender, they’re sweet and tart, and they’re topped with a generous sprinkling of buttery oat streusel (the best part of any muffin, IMO). And they’re perfect for making quick use of rhubarb in its prime as we’re turning the corner into berry season.