Preheat oven to 350 degrees F. Generously butter 24 3-inch muffin tins. In a small bowl combine the pumpkin, vanilla, eggs, oil, and sugar. In a separate bowl sift together the flour, baking powder, soda, cinnamon, and salt. Combine wet and dry ingredients; beat until smooth. Add raisins and pour batter into muffin tins, filling each cup 2/3 full. Bake for 25 to 30 minutes, until lightly brown.