Preheat the oven to 350˚F. Line a muffin pan with paper liners and set aside.
In the bowl of a stand mixer, cream together the sugar and butter. Add in the eggs one at a time, mixing until fully incorporated.
Add in the flour, baking powder, baking soda and salt, and mix until fully combined. Fold in the sour cream and vanilla, and mix until smooth.
Divide evenly into the prepared muffin pan, and bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the centre comes out clean.
Allow the muffins to cool in the muffin pan for 5 minutes, then transfer to wire racks to cool completely.