Step 1

Arrange a rack in the middle of the oven and heat to 350°F. Line 2 baking sheets with parchment paper or a silicone baking mat; set aside.

Step 2

Whisk the flour, baking powder, and salt together in a large bowl; set aside.

Step 3

Whisk the eggs and 1 cup of the sugar in a large bowl until smooth. Add the oil and vanilla and continue to whisk until you have a smooth, glossy mixture that's slightly thickened. Switch to a sturdy rubber spatula, add half of the flour mixture, and stir until the flour disappears into the mixture. Add the remaining flour mixture and stir — you'll need to put a bit of muscle into this — until it's almost incorporated. Add the chocolate and continue mixing until you've got a thick, sticky dough.

Step 4

Starting close to one long side of one of the baking sheets, drop, spread, and cajole 1/3 of the dough into a log about 3 inches wide and 12 inches long. (Get the width, and whatever the length is will be fine.) Make a second log in the center of the baking sheet, and a third one close to the other long side of the sheet. It's not a neat job and your logs won't be pretty, but it won't matter.

Step 5

Stir the remaining 2 tablespoons of sugar and cinnamon together in a small bowl. Sprinkle some over the logs, saving the rest for the second bake. (You'll have more than you need, so be generous.)

Step 6

Bake for 20 minutes. Rotate the baking sheet from front to back and bake until the logs are golden brown on top and deeply golden brown on bottom, 15 to 20 minutes more. They'll crack a little, and that's okay. Place the baking sheet on a wire rack.

Step 7

When the cookies are cool enough to handle but still warm, transfer to a cutting board. Using a serrated knife, cut the logs on the diagonal into 1/2-inch wide slices. Transfer the slices cut-side down onto the second baking sheet. Sprinkle the cookies with more cinnamon-sugar and bake for 10 minutes more. Place the baking sheet on a rack and let the cookies cool completely.