Preheat the oven to 400°F (200°C). In a small saucepan, cover the red lentils with water by about an inch, and bring to a boil; simmer for 15-20 minutes, until the lentils are very soft. Drain well in a sieve and set aside.
In a large bowl, stir together the flour, oats, brown sugar, baking powder, baking soda, cinnamon and salt; set aside. In a medium bowl, stir together the applesauce, yogurt, oil and egg. Add to the dry ingredients along with the cooked lentils and stir until almost combined; add the raisins and stir just until blended.
Divide the batter among 12 paper-lined muffin cups, filling them. Bake for 25-30 minutes, or until golden and springy to the touch. Tilt them in their pans to help them cool.