Mix filling ingredients with mixer; set aside.
Preheat oven to 350 degrees (175 C.).
Oil bottoms only of medium muffin tins.
Beat eggs; stir in milk and oil; set aside.
Mix together flour, sugar, baking powder, and salt until well blended.
Pour liquids, all at once, into flour mixture; stir until moistened.
Fill muffin cups about 1/2 full.
Spoon 1 tsp (5 ml) filling onto batter.
Top with batter to 3/4 full.
Bake 30 to 35 minutes.
Don't brown; should be light in color.
Roll hot muffins in powdered sugar.