Sift together the flour, sugar, baking powder and salt.
In another bowl, beat the egg, add the milk and the melted butter.
Pour over the dry ingredients, stir just enough to moisten the whole.
Stir in the blueberries.
Spoon into microwave-safe muffin pan lined with paper baking cups.
Mix together the lemon rind and sugar.
Sprinkle a bit on each muffin.
For a 6-muffin mold, microwave at HIGH 2 to 2 1/2 minutes.
Test doneness.
If necessary, microwave another minute at MEDIUM.
Helpful hint: To freeze your own blueberries: Wash them and dry them on a cloth.
Place 1 teaspoon (5 mL) sugar in the bottom of each container or freezer bag.
(Do not freeze more than 2 cups (500 mL) per container).
Place prepared berries on top of sugar.
Do not mix.
Cover with a little square of crumpled waxed paper.
Cover container or close bag.
Freeze.
Prepared this way, the thawed blueberries look like fresh ones.