Line a 12-hole muffin pan with paper muffin cases.
Sift flour, cocoa and bicarbonate of soda into a large bowl.
Stir in sugar and choc bits and make a well in the centre.
In a small bowl, use a fork to whisk together margarine, milk and egg, then add to flour mixture.
Stir gently until mixture is just combined (do not over-beat).
Gently fold raspberries through mixture.
Spoon mixture into cases.
Bake for 20-25 minutes or until muffins are well risen and spring back to the touch.
Leave in pan for a few minutes, then transfer to a wire rack to cool.
TIP: When muffins are cool, package individually in freezer bags and freeze. Muffins can be thawed in the microwave as needed. Alternatively, place a frozen muffin in your training bag in the morning. It should be thawed in time for a post-training recovery snack