**Tip: always mix your muffin batter until the ingredients are just combined, don't over-mix. If you over-mix, you will end up with cupcake texture or even a flat muffin.**
Preheat the oven to 400.
Beat the butter and sugar for a couple of minutes.
(On low) mix in the egg, milk and vanilla until just incorporated.
(Still on low) Mix in the flour, baking powder and salt until just incorporated.
Fold in the cranberries and white chocolate chips.
Grease the muffin pan with PAM and add the matter, 3/4 way full.