Step 1

Microwave chocolate, cocoa, and butter in bowl at 50 percent power, stirring often, until melted and smooth, 2 to 4 minutes; let cool slightly. Working in 4 batches, grind Sucanat in spice grinder until fine and powdery, about 1 minute.

Step 2

Combine ground Sucanat, flour, baking powder, baking soda, and salt in bowl. In large bowl, whisk cream, egg and yolk, and vanilla together. Whisk in cooled chocolate mixture. Stir in flour mixture using rubber spatula until combined; dough will be stiff and dry.

Step 3

Cover bowl with plastic wrap and let rest at room temperature for 30 minutes. Adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 degrees. Line 2 baking sheets with parchment paper.

Step 4

Working with scant 2 tablespoons dough at a time, roll into balls and space 2 inches apart on prepared sheets.

Step 5

Bake cookies until edges have just begun to set but centers are still very soft, about 10 minutes, switching and rotating sheets halfway through baking. Let cookies cool completely on sheets. Serve.