Better-for-You Grilled Cheese Sandwich

Cooking this like I make my usual grilled cheese sandwiches, until cheese is throughly melted, I found this recipe is too runny. I think it's the tomato that makes the cheese so runny. I love grilled cheese sandwiches that when you take a bit, a string of cheese follows but this had a string of cheese that dripped...to runny to stretch. It was good but I wouldn't make it again.