Preheat the oven to 160°C. Line or grease a square baking pan.

In a microwave-safe bowl, combine the butter and the ½ cup of dark chocolate (not the chips). Microwave in 30-second intervals, stirring between each, until melted (about 1½–2 minutes total). Set aside to cool slightly.

In a large mixing bowl, whisk together the eggs, coconut sugar, honey, and vanilla extract. Stir in the melted butter-chocolate mixture until smooth.

Scrape down the sides of the bowl. Add the flour and unsweetened cocoa powder. Mix until just combined. Don’t overmix.

With a spatula, gently fold in the 1 cup sugar-free chocolate chips.

Spread the batter evenly in the prepared pan. Bake in the center of the oven for 25-30 minutes, or until the edges are set but the center is still slightly soft.

Allow to cool in the pan for about 15 minutes. While still warm, press extra chocolate chips on top if desired.

Slice and serve.