For the bacon and plum muffins, preheat the oven to 180 °C. Line a muffin tray with paper cups. Finely dice the bacon and the plums, cut the onion into rings.
Fry the bacon and onion in a little oil and add the plums. Deglaze with sherry and reduce and pepper. Mix flour, baking powder, cumin and salt.
Whisk in the oil, yogurt and eggs until well blended, then stir in the bacon mixture. Quickly mix with the flour mixture, do not stir too long or the batter will not be fluffy) and pour the batter into the ramekins.
Bake the bacon plum muffins for about 25 minutes, let cool and enjoy.