Pre-heat oven to 350 degrees.
In medium mixing bowl, combine dry ingredients and set aside. In a separate bowl, mix milk, yogurt, egg, syrup, and vanilla until well combined. Gradually whisk in melted butter.
Stir wet ingredients into dry until well combined. Gently fold in chopped prunes.
Grease muffin pan or use liners. Scoop the batter into prepared muffin cups, filling completely. Bake at 350 degrees for 12-15 minutes. Remove from the tin and place on a cooling rack to avoid steaming the bottoms of the muffins.