You imbue your body or weapon with power to assist with striking your targets and cause the attacks to release flame upon them. Until the end of your current turn you may use your spellcasting ability instead of the normal ability (such as Strength or Dexterity) used for any melee attack you make. In addition, when you hit a creature or object with a melee attack it deals an additional 1d6 fire damage. This additional damage can only be dealt once. 

The additional damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).