Cauliflower Steaks with Herb Salsa Verde

Name: Cauliflower Steaks with Herb Salsa Verde
Ingredients: 1/4 cup chopped flat-leaf parsley; 2 tablespoons chopped cilantro; 2 tablespoons chopped tarragon; 1 1/2 tablespoons drained capers, coarsely chopped; 6 cornichons, finely chopped; 1 small garlic clove, minced; 1 tablespoon Dijon mustard; 1 tablespoon grainy mustard; 1/3 cup extra-virgin olive oil; 1 large head of cauliflower; Kosher salt; Freshly ground pepper; 2 tablespoons canola oil; 1/2 cup dry white wine; 1/2 teaspoon finely grated lemon zest; 4 1/2 tablespoons fresh lemon juice; 1 teaspoon red wine vinegar