Blueberry muffins

Oil or melted butter for greasing(if using) 2 cups all-purpose flour 1 tbsp baking powder 1/8 tsp salt heaping 1/2 cup firmly packed light brown sugar scant 1 1/2 cups frozen blueberries 2 large eggs 1 cup milk 6 tbsp sunflower oil or melted, cooled butter 1 tsp vanilla extract finely grated rind of 1 lemon  Preheat the oven to 400 degrees. Grease a 12-cup muffin pan or line with 12 muffin paper liners. Sift together the flour.baking powder, and salt into a large bowl. Stir in the sugar and blueberries.  Lightly beat the eggs in a large pitcher or bowl,then beat in the milk,oil,vanilla extract and lemon rind. Make a well in the center of the dry ingredients and pour in the beaten liquid ingredients. Stir gently until just combined; do not overmix. Spoon the batter into the prepared muffin pan. Bake in the preheated oven for about 20 min. until well risen.golden brown, and firm to the touch.  Let the muffins cool in the pan for 5 min. then serve warm or transfer to a wire rack and let cool completely.  Makes 12 muffins.