Preheat the oven to 375 degrees F.
Prepare a muffin tin with baking spray or paper muffin cups.
In a mixing bowl, cream together the butter and sugar until light and fluffy. Add in the eggs, one at a time. Add in the vanilla and lemon zest.
In a separate bowl, sift together the flour and baking powder. Add in the salt. Add the wet then dry ingredients into the butter/sugar mixture alternately (dry, wet, dry, and wet).
Carefully fold in the cranberries. Spoon the batter into a muffin tin and bake at 375 degrees Fahrenheit until golden brown, about 15 to 20 minutes or until a toothpick inserted in the middle comes out clean. Cool on a wire rack.
Enjoy!