In a large bowl, combine the flour, sugar, baking powder and salt with a wire whisk. In a medium bowl, beat the milk, melted butter, egg, vanilla extract and lemon zest with a fork until well blended.

Add the milk mixture to the the flour mixture and stir until just combined (the batter will be lumpy.) Fold in the raspberries.

Fill the muffin-pan cups two-thirds full with batter. Bake until a toothpick inserted in the center of the muffin comes out clean, 20-25 minutes. Allow to cool for 1 minute, then remove muffins from pan.

Finish cooling on a wire rack. Drizzle glaze over cooled muffins. Store leftovers in a sealable container.

To make the glaze, place the powdered sugar in a medium bowl. Add the lemon juice and stir until well mixed.