3/4 Cup (1-1/2 sticks) unsalted butter, room temperature, plus additional for pan
7 Tbsp Maple Sugar Powder, divided
1/4 tsp Kosher Salt
1-1/2 Cups all purpose flour
1/4 Cup bittersweet chocolate chips
2 tsp Runamok maple syrup
Preheat oven to 300°F. Butter a 9-inch diameter tart pan with removable bottom.
Using electric mixer, beat room-temperature butter, 6 Tbsp Maple Sugar, and coarse salt in large bowl until light and fluffy and sugar is dissolved. Add flour and beat just until blended.
Pat dough evenly onto bottom of prepared pan. Press chocolate chips into dough in random pattern, spacing chips 1/2 inch apart (chips should show). Using a dinner knife, lightly score the dough. [This will make it easier to cut baked shortbread into tidy wedges later.]
Brush dough with maple syrup and sprinkle evenly with remaining 1 Tbsp Maple Sugar.
Bake shortbread until golden-brown and firm to touch, about 55 minutes. Transfer pan to rack and cool shortbread 10 minutes.
Gently push tart pan removable bottom up, releasing shortbread. Cut warm shortbread into 16 wedges. Cool shortbread wedges completely and serve.