Tomato Tuna Melts

By Ann Fulton

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Light on mayo and big on flavor, two of these speedy Tomato Tuna Melts deliver 25 grams of protein with just 10 grams of carbohydrates and 289 calories.


Most Mondays since the early ‘90s, my father has eaten a tuna melt. He belongs to a men’s lunch group that meets weekly, and after all this time, his buddies would likely be shocked if he deviated from the predictable menu choice.

What my dad orders is the traditional open-face melt served, as expected, on bread. While I would never suggest a change to that weekly lunch order, my dad has given his stamp of approval to a slightly different way of enjoying this classic comfort food.

In this seasonal twist, vine-ripened tomatoes stand in for the bread, creating a fresh-tasting melt that’s not quite a sandwich yet can still be the centerpiece of a simple, light meal. The melts are easy to throw together, can be partially prepped in advance, and the cook time is brief.

In my day-to-day cooking, I lean towards mostly wholesome ingredients and an everything-in-moderation approach rather than calculating carbs, calories, and so on. When I share a recipe that seems to conform to a low-carb, high-protein diet plan, however, I often receive a handful of requests for a few key numbers.

For those who like more detailed information on a regular basis, I have a link to a recipe calculator under the “Helpful Tips” tab. When clicked on, you’ll be led to a free tool provided by Simply enter the ingredients used in any of your recipes, being sure to note the number of servings. For today’s recipe, I picked out the most frequently requested values.

With 10 grams of carbohydrates, 25 grams of protein, and 289 calories for the larger, two-serving (main dish) option, this easy meal offers a convenient, great-tasting option for those looking to limit calories, consume a higher ratio of protein to carbs, and/or avoid gluten–or simply chip away at an overload of tomatoes! 

Light on mayo and big on flavor, two of these speedy Tomato Tuna Melts deliver 25 grams of protein with just 10 grams of carbohydrates and 289 calories.

Tomato Tuna Melts
Yield: 2 main dish servings or 4 side dish servings -- recipe may easily be doubled
Light on mayo and big on flavor, two of these speedy melts deliver 25 grams of protein with just 10 grams of carbohydrates and 289 calories.
  • 2 large (about 5-6 ounces each) Roma or plum tomatoes*
  • Kosher salt and freshly ground pepper
  • 1 (5-ounce) can tuna in water, slightly drained
  • 2 tablespoons (26 grams) mayonnaise
  • 3 tablespoons minced celery
  • 1 tablespoon minced red onion
  • 1 teaspoon fresh lemon juice
  • 1/8 teaspoon dried dill
  • 2 ounces cheese (about 1/2 cup shredded or 4 slices; Cooper sharp is our favorite, but cheddar cheese, mozzarella and Italian blends are all delicious)
  1. Slice the Roma tomatoes in half long-ways so you have 2 long ovals. Gently scoop out as many seeds as you can, leaving the flesh. Season to taste with salt and pepper. If you have time, allow the tomatoes to sit on the counter for 15-20 minutes. The salt will draw out excess moisture, and you can pour this off before proceeding. If you don’t have time, the finished tomatoes will have a bit more water content but will still be delicious.
  2. In a small bowl, combine the tuna, mayonnaise, celery, onion, lemon juice, dill and a few grinds of the pepper mill. The tuna salad may be prepared several hours in advance, covered and refrigerated.
  3. Preheat the broiler to high. If the tomatoes have been sitting, pour off any moisture that has collected inside. Stuff each tomato half with one quarter of the tuna salad. Arrange the cheese on top; if using sliced cheese, break to fit, allowing it to extend a few millimeters over the edge. (Depending on tomato proportions, you may not need four full slices.) Arrange the tomatoes on a baking sheet, and broil the tomatoes until the cheese is melted with a few golden brown spots on the top, about 1 to 2 minutes. Make certain to watch very closely after the first minute so as not to burn the cheese.** Remove from the oven and enjoy immediately. For a pretty look, you may wish to garnish the plate with fresh herbs, if available.
  4. Cool, cover and refrigerate any uneaten melts. Served cold, the leftovers make a welcome lunch.
  • *Roma/plum tomatoes work well because they tend to have a lower moisture content than standard tomatoes, but either may be used. To avoid a watery cooked tomato in either case, but especially with a beefsteak or similar variety, gently squeeze or scoop out as many seeds as you can. Then follow the salting and draining suggestion above. You may also three or four smaller tomatoes, adjusting the tuna and cheese distribution accordingly.
  • **A quick broil melts the cheese but allows the tomatoes to keep most of their structure. Baking the tomatoes over a longer period of time makes them softer than I prefer. If you would like the tomatoes to be slightly softer throughout, turn the broiler off after the cheese is melted and place the tomatoes on the lowest shelf in the still-hot oven for a minute or two.
  • If the stuffed tomato halves don’t sit completely upright on the baking sheet, wedge something like a bean or a small piece of produce scrap under the side that’s tilting down. This will ensure that all the cheese broils evenly.
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  1. Elaine

    Ann I made this for lunch today – delicious!! I used provolone cheese and Washington Borough Roma tomatoes. Thanks so much.

  2. S.S. Post author

    I made your tuna melts last night and loved them. I doubled the tuna so I would have for lunch. Finishing it off today with some thin crisp triscuts! So good!

    Also, I joined Weight Watchers online to kind of “reset”. They have changed which nutritional values they use to determine food point values – now taking sat fat and sugar under consideration. Anyway, 5 oz of tuna is only 1 point! And I can have 36 in a day. The mayo adds another 2 points (I use half), but still–even counting the cheese your tuna melts are a VERY low point dinner choice- allowing me to have just a small bit of vanilla ice cream with my peaches last night!

    1. Ann Post author

      I’m thrilled these were a hit and appreciate the helpful Weight Watchers information. Thank you for passing it along!