Chewy Marble Sugar Cookies - chocolate

Method

• Preheat oven to 375 degrees F. Line 2 large sheet pans with parchment paper.
• Cream butter and sugars for 1 minute. Scrape sides of bowl. Continue beating for another minute. Scrape bowl again.
• Add vanilla. Beat for 1 minute. Scrape sides of bowl.
• Add egg yolks. Beat for 1 minute. Scrape sides of bowl.
• Add flour, salt and baking soda. Beat 1 minute. Scrape sides of bowl and beat for another minute
• Make a well in the middle of dough and pour in the melted chocolate. Gently fold the dough over with a spatula or knife, until you achieve a marbled look. Don't overmix the dough, or you'll have a chocolate cookie instead of a marbled cookie, which isn't a bad thing, it just won't look as cool.
• Place course sugar in small, shallow bowl. Using a small cookie/ice cream scoop (mine is 1 1/2" in diameter) dipped in a mug of hot tap water, scoop balls of dough and drop two at a time into the course sugar. The hot tap water gives the dough balls a little tackiness and helps to get the course sugar to stick. Gently roll around in the sugar (the dough balls, that is.) Place balls of dough on parchment, leaving about 1 1/2" space around each. My half-sheet pans fit 12 cookies very comfortably.
• Do not press the balls down. This will ensure a chewy middle.
• Bake for 8 - 10 minutes, turning and reversing pans midway through baking. Resist the urge to bake your cookies longer, or they won't be very chewy.
• Place pans on cooling racks. When cool, store cookies in air-tight containers.