Grilled cos lettuce and bacon salad

Ingredients

• 6 bacon rashers
• 1/3 cup whole egg mayonnaise
• 2 tbsp buttermilk
• 1 tbsp white wine vinegar
• 1 clove garlic, crushed
• 1 tbsp finely chopped chives
• 5 heads baby cos lettuce, halved lengthwise, rinsed and dried
• 3 gourmet tomatoes, chopped
• Salt and freshly ground black pepper, to taste
• 80g parmesan cheese, grated