In a large bowl or a mixer, add the butter, sugar, egg and vanilla extract. Beat together for a few minutes until combined.
To this mixture add the flour, salt, baking powder and baking soda. Gently combine together. I like to mix this with a wooden spoon.
Add the chocolate chips and the walnuts and mix well.
Preheat the oven to 200°C or 400°F.
Once done, divide the mixture into six, about 150g each.* Place in the ramekins and press the cookie dough down. If you want an extra molten heart, add some more chocolate chips in the centre and cover with the cookie dough. Place in the fridge for about 30 minutes before baking. **
Bake the cookies in the ramekins for about 15 minutes. If you want them to be more done bake for 20 minutes.
Once ready, let them rest for a few minutes, as the chocolate centre can be too hot.
Serve with a sprinkle of flaky salt, ice cream or whipped cream.