First, roast the plums. Preheat the oven to 200 C. Run a sharp knife along the center of each plum, till the knife touches the stone. Twist the plum gently and pull apart the two halves. Prise the stone out and place the halves, cut side up, on a baking tray. Repeat with the rest of the plums, then sprinkle on the sugar. Bake for 10 minutes until the plums are soft and have released some of their juices. Set aside to cool. <br></br>

While the plums are roasting and then cooling, brown the butter. Place the butter in a small saucepan over low to medium heat. Watch it constantly as it melts, then foams a bit, then begins to turn clear and golden-brown colour with a few browned bits at the bottom. Scrape as you stir.

If it is still foaming, stir gently till you can see the liquid and smell a nutty aroma. The whole process shouldn't take more than 3 to 4 minutes. Turn off the heat and set aside to cool. <br></br>

Meanwhile, chop the roasted plums into smaller pieces. If they are too soft, don't worry about perfect pieces, just make sure there are no huge chunks which could cause the muffins to break. <br></br>

Preheat the oven to 190 C, grease 12 muffin moulds or line with cupcake liners. <br></br>

In a large bowl, sift the flours, baking powder, baking soda, cinnamon and salt, if using. Add the poppy seeds and stir. Set aside. <br></br>

In another bowl, lightly beat the egg, then add the sugars and mix well. Add the browned butter and yoghurt, and mix again. <br></br>

Fold in the flour mixture, and finally, gently fold in the plums. If they release some juices, it's ok. The muffins will be that much more delicious! <br></br>

Divide the batter equally among the muffin moulds, and bake for 15 to 20 minutes, until golden-brown on the top and a toothpick poked in the center comes out clean. I wanted the tops to be nice and brown, so turned on my oven's broil setting in the last minute. <br></br>

Allow to cool before digging in, because the plums make the muffins pretty fragile. <br></br>