Thinly slice the rhubarb (approx. 5 mm) and cut the pear into wedges. Chop the rosemary. Mix rhubarb, pear, SteviaSweet Crystal and spices and place in a greased oven dish.
Combine the soft butter, oat flakes and SteviaSweet Crystal into a crumbly mixture. Then spread this mixture evenly over the rhubarb. Put the crumble on the middle rack in the oven and bake for about 20 minutes or until it is golden brown.
Whisk the cream, yoghurt and spices and serve with the hot rhubarb and oat crumble.