Grilled Steak Tacos with Chipotle Cream and Chimichurri

Name: Grilled Steak Tacos with Chipotle Cream and Chimichurri
Ingredients: 1 small bunch fresh cilantro, leaves picked; 1/2 medium yellow onion; Juice of 1 1/2 limes; 1/2 teaspoon crushed red pepper flakes; 4 ounces sour cream; 1 large chipotle pepper in adobo, finely diced, plus 1 tablespoon adobo sauce; Mixed greens; 6 small fajita-size flour tortillas, warmed; 1 pound skirt or flank steak; 7 cloves garlic; 1 teaspoon Dijon mustard; 1/4 cup, plus 2 tablespoons olive oil; 1/3 cup, plus 2 tablespoons red wine vinegar; Kosher salt and freshly ground pepper