These easy toasted sandwiches are the perfect way to enjoy juicy large heirloom tomatoes! With toasted ciabatta, melted cheese, pesto mayo and any little flavor morsels you care to add, these are a filling, quick, and easy meal.

So. You have a big plump heirloom tomato and you want to make an epic sandwich with it. This has been my mission ever since the tomato season kicked off: to make an amazing sandwich that can handle some seriously thick juicy tomato slices.

And what I have for you today is simply delightful. Toasted ciabatta with melted cheese is our base, and we pile it with heirloom tomato slices, some olives and onions, all smothered in a creamy pesto mayo sauce. And it is just perfect and easy summer eating.

You can make this for lunch, but adding the right side dishes can make it a viable candidate for a hearty dinner.

What you need to build the perfect Heirloom Tomato Sandwich

In the process of perfecting this sandwich I’ve tried various breads, toasted versus untoasted, various cheeses, various spreads, various other additions, and here are my general findings:

  • The tomatoes should be room temperature. Never let those tomatoes see the inside of a fridge, my friends, and don’t toast the sandwich with the tomato in it. Keep them at fresh, juicy, room temperature perfection. It can be any heirloom or beefsteak variety but look for plump, round types which can be sliced into thick, large, flat slices where possible.
  • The bread should ideally be ciabatta. I know you might already have a bread in mind to use, in which case, go ahead. But if you’re buying bread especially, take note: I tried all sorts of breads for this recipe and ciabatta just wins. It is thick and sturdy enough not to get soggy from the tomato juice. And it has nooks and crevices that the tomato juices and the sauce can sit in, so you aren’t getting very much dripping out the sides.
  • Two cheeses are better than one. I like to have a mild, melty cheese like gouda or mozzarella AND a stronger, more flavorful smoked cheese in the mix (I used smoked cheddar but provolone would be great too). Of course, just one cheese is fine and it can be any cheese if this is a question of pulling together a sandwich with what you already have.
  • Some olives and sliced onions are delightful little flavor additions but use them sparingly. Feel free to add capers or pickled onion any other little additions you have to hand.
  • Whipping up a quick pesto mayo is well worth the effort here. Pesto brings some delicious tangy basil flavor, and mayo brings creaminess; neither are good enough on their own, but together they are perfect. I use jarred pesto for this, but it’s also a great way to use up some homemade pesto – if you make a batch, just save a tablespoon to make this mayo with the next day. And I wouldn’t hesitate to try different pestos such as cilantro (coriander) pesto for this recipe.

Pesto Mayo Alternatives

If you don’t have any pesto, there are plenty of alternatives that would do well in this sandwich:

Serving Suggestions

  • This recipe can serve 2 or 4, depending on appetite and side dishes. A whole sandwich is pretty massive and might be too much for one, especially if there are side dishes, but I will let you be the judge of that!
  • For an easy side dish, you can never go wrong with a batch of Air Fryer Rosemary Fries. With the fries as a side dish, this recipe can definitely serve 4.
  • A salad is also a good option: try this Chickpea Salad or this Bulgur Salad for something hearty and easy.
  • Going for a soup and sandwich combo? This Potato Soup would be ideal.

More Heirloom Tomato Recipes

If you have a bounty of these amazing tomatoes, lucky you! I have plenty more ideas for how you can use them up…

Heirloom Tomato Sandwiches

These easy toasted sandwiches are the perfect way to enjoy juicy large heirloom tomatoes! With toasted ciabatta, melted cheese, pesto mayo and any little flavor morsels you care to add, these are a filling, quick, and easy meal.
No ratings yet


  • 2 individual sized ciabatta loaves, or one full sized loaf, halved
  • 2 medium heirloom tomatoes, cut into thick slices
  • 2 thick slices smoked cheese or provolone, or a handful of grated
  • 3 thick slices gouda or swiss cheese, or a handful of grated
  • red onion slices, to taste
  • sliced olives, to taste

Pesto Mayo

  • 2 tbsp mayonnaise
  • 1 tbsp basil pesto
  • ½ tsp dijon mustard
  • ¼ tsp honey


  • Prepare the pesto mayo sauce by whisking together all of the ingredients in a small bowl. Cover and set aside.
  • Pre-heat the grill or broiler. Slice the ciabattas open and spray or brush with olive oil. Place under the grill / broiler until they are browned and toasted.
  • Remove the top slices of the ciabatta from the tray. Arrange the cheese over the bottom slices of the ciabatta. Make sure that the browned edges are all covered by cheese – this will stop them from burning.
    Place the ciabatta bottom slices back under the grill / broiler until the cheese has melted. It will only take a few moments for the cheese to start bubbling so keep a very close eye on them.
  • Now you can assemble the sandwiches! Arrange the tomato slices over the bottom of the ciabatta. Add salt and pepper, then the onion and olives. Spoon the pesto mayo over the top and then cover with the top of the ciabatta.
  • Slice and serve!
Calories: 739kcal, Carbohydrates: 70g, Protein: 31g, Fat: 37g, Saturated Fat: 16g, Polyunsaturated Fat: 7g, Monounsaturated Fat: 9g, Trans Fat: 0.03g, Cholesterol: 88mg, Sodium: 1.474mg, Potassium: 302mg, Fiber: 3g, Sugar: 5g, Vitamin A: 1.467IU, Vitamin C: 12mg, Calcium: 552mg, Iron: 1mg