In a large bowl, add and combine well:
2 eggs
.5 cup oil
1 cup milk
1 tsp vanilla
In a smaller bowl, combine well:
1.75 cup all-purpose flour, unsifted
.5 cup sugar
.25 cup pure cocoa
1 tbsp baking powder
.5 tsp salt
.5 cup peanut butter

Combine wet and dry mixtures and fold together gently until just mixed. Spoon into prepared pan. Bake at 200 C (400 F) for 20 minutes. Remove from pan and cool on rack. Makes 10 medium-sized muffins.