Preheat the oven to 190°C (375°F).
Line a 12-cup muffin tin with paper liners.
In a large bowl, whisk together the flour, sugar, baking powder, and salt.
Make a whole in the dry ingredients and add the whisked egg, milk, oil, and vanilla
Stir gently, just until no dry flour remains. Do not overmix.
The batter should be thick but soft.
If you're making half a batch with chocolate and the other half with cranberries, divide the batter evenly into two bowls. If not, simply fold in the cranberries and move on to step 9
Fold the dried cranberries into one half. Fold the chocolate chips into the other half.
Spoon the batter into the muffin cups, filling them nearly to the top.
Bake for 15–18 minutes, or until a toothpick inserted into the center comes out clean.
Let cool slightly, then enjoy warm — preferably with coffee.