2. Mix dry ingredients together in medium-sized bowl.
3. Using an electric hand mixer or stand-up mixer, combine butter and caster sugar until fluffy. Add the light muscovado sugar, eggs and vanilla extract. Mix again.
4. Last, add the chocolate chips and combine.
5. Place spoon-sized dollops of cookie dough on two ungreased baking sheets. Bake 7-8 minutes for soft cookies and 10 minutes for crisp cookies.
6. Let cool on tray for at least two minutes before removing. Transfer to a plate, wire rack or greaseproof paper to finish cooling.
