Pre heat he oven top 180C / 350 F (middle rack) and line a baking sheet with paper.

In a large heatproof bowl heat he butter and chocolate until just melted, stirring constantly (you can do this either over a double boiler or in the microwave - I did it in the microwave) - be careful not to over heat the chocolate.

Stir in the sugar, salt and vanilla. Mix. Add the eggs, one at a time, until completely mixed in.

Add the flour and baking powered to the bowl and stir to combine. Stir in half to 3/4 of the chopped nuts (better to add 3/4)

Scoop the batter using a small ice cream scoop into 12 balls spacing them evenly on the pan. Sprinkle the remaining nuts over the top of each cookie.

Bake until the cookies are puffed, cracked and barely set, about 8 minutes. Do not over bake.

Let the cookies cool on the pan for 5 minutes, then transfer to a wire cooling rack