1. Melt 3/4 cup chocolate chips gently in the microwave or over a pot of
simmering water (bain-marie). Set aside to cool.
2. Sift flour, cocoa powder, baking soda, and salt together in a bowl, and stir together.
3. Beat the butter and sugar together until thick and creamy. Beat in eggs one by one. Add cooled melted chocolate and vanilla extract. Continue beating until ingredients are well mixed.
4. Fold dry ingredients and 2 1/4 cups chocolate chips into the mix and stir until combined.
5. Scoop cookie with a 1 tablespoon scoop (if the mix is soft you can pop it in the fridge to stiffen up and this will make it easier to scoop).
6. Bake at 350 degrees F for 8 to 9minutes. Take care not to overbake as these cookies should be almost brownie-like.
7. Once baked, pop a marshmallow on top and put it back in the oven on broil for 1-2 minutes for a lovely toasted effect.