In a double boiler, melt the butter and chocolate until smooth. Set aside.<br></br>

Preheat the oven to 175 C and lightly grease a baking sheet or line with a silicone mat.<br></br>

Sift the buckwheat flour, arrowroot and baking powder in a large bowl. Set aside.<br></br>

In a mixing bowl, beat the eggs and sugar with a hand mixer, for about 5 minutes until pale and fluffy (or use a stand mixer, though I found it harder to beat the eggs well in this, as the bowl is much larger than needed)<br></br>

Add the vanilla and the melted chocolate mixture and beat for a few seconds to combine.<br></br>

Add the flour mixture and beat until just combined. Fold in the chocolate chips. The dough will be shiny, and may ball up.<br></br>

Scoop out the dough in a tablespoon measure and drop on to the baking sheet. I got 18 cookies, but you may get more or less depending on the thickness of the dough.<br></br>

Bake for about 10 minutes until the cookies have cracked on the top, the edges have set and the middle is no longer wet. You may need to press them down to flatten. Best eaten warm!!