Lamb Meatball Sandwiches with Saffron Sofrito

Name: Lamb Meatball Sandwiches with Saffron Sofrito
Ingredients: 1 pound ground lamb; ¼ pound ground pork; ¼ cup chopped flat-leaf parsley; 2 teaspoons chopped fresh mint leaves; 1 teaspoon fresh thyme leaves; Zest of 1 lemon; ½ teaspoon chile powder; ¼ teaspoon cayenne pepper; Kosher salt; 2 tablespoons extra-virgin olive oil; 1 cup finely diced yellow onion; 1 cup white wine; ½ teaspoon crushed saffron threads; 1 cup stewed canned tomatoes (such as muir glen), roughly chopped; 4 italian or french rolls, split lengthwise