Chocolate filled vanilla muffins (v)

Adapted from jam-filled muffins in Muffin Mania.
Makes a half-batch (6), or double the ingredients for a full batch.
Original post (with pictures) here.

1 cup plain flour
1/4 cup white sugar
2 tsp baking powder
Pinch salt
Egg replacer to the equivalent of 1 egg (or 1 egg)
2 tbsp oil
2 tbsp soy milk
3/4 cup soy yoghurt (I used vanilla, as it's the closest to plain I've been able to find)
1 tsp vanilla
~50g chocolate squares, cut in half, or chocolate chips

1. Preheat oven to 180'C fan-forced, and grease and line a 6-pan muffin tray. If using chocolate squares, cut them in half.
2. Combine the flour, sugar, baking powder and salt in a medium bowl.
3. In a separate bowl, prepare the egg replacer (or egg) and combine with the oil, milk, yoghurt, and vanilla.
4. Add the wet ingredients to the dry, and mix until just combined.
5. Fill each muffin tray ~2/3 full, and then add 1/2 a chocolate square (or a decent sprinkling of chocolate chips) to each.
Cover with the remaining muffin mix, and sprinkle grated chocolate or extra chocolate chips on top.
6. Bake for ~15 minutes.