Herbal Mayonnaise: In a bowl whisk mayonnaise, lemon juice, zest and garlic powder. Fold-in cilantro, fresh herbs, salt and pepper. Whish until mayonnaise is combined.
Toast country bread, spread with Herbal Mayo, add lettuce, Smoked Gouda cheese, Maui onion, English cucumber, Heirloom tomato, Hass avocado and top with lettuce. Slice sandwich in half and place on serving plate.