Memphis Barbecue Co.’s Melissa Cookston is known for her prowess cooking meat (she’s the only female barbeque grand champion in the world and has won dozens of barbeque competitions across the globe), but she had plenty to say about leafy vegetables. Thanks to an abundant CSA share, I spent this past summer grilling heads of romaine. The result is fantastic: lovely charred greens with a touch of caramelized flavor. Wondering what other greens I should be grilling, I reached out to an expert. Memphis Barbecue Co.’s Melissa Cookston is known for her prowess cooking meat (she’s the only female barbeque grand champion in the world and has won dozens of…