Step 1

Preheat oven to 350°F. Line a 9x9 square cake pan with parchment paper, leaving 2 ends hanging over the edge of the pan. Grease the parchment with baking spray or butter/oil and flour.

Step 2

In a small bowl, whisk together the flour, cocoa powder, baking powder, kosher salt, and ground ginger. Set aside.

Step 3

In the top of a double boiler or in a large heatproof bowl over a pot of simmering water, melt the butter, oil, and unsweetened chocolate, stirring occasionally, until melted and uniform. Remove from heat.

Step 4

Whisk in both sugars until combined, then add the eggs, whisking until glossy and smooth, about 45 seconds. Fold in the dry ingredients, the 3/4 c chocolate chunks and the 1/2 c candied ginger pieces. Spread batter into the prepared pan. Sprinkle with the remaining chocolate chunks and candied ginger pieces.

Step 5

Bake for 30-35 minutes, or until a toothpick inserted into the center of the pan comes out with only a few moist crumbs. Sprinkle with flaky sea salt, if desired. Cool completely, then cut and enjoy!