Low-carb pizza with tuna, onion, and olives

The Low Carb Tuna, Onion, and Olive Pizza is a tasty, Mediterranean-style recipe suitable for a ready-made pizza base.

The topping combines tomato sauce, mozzarella, well-drained tuna, and a controlled amount of onion and olives. The most important technical point is to limit moisture: the tuna and mozzarella must be well drained, and the tomato sauce should be thick.

The onion is used in a small quantity and sliced very thinly so that it cooks evenly without overpowering the flavor of the other ingredients.

For this recipe, you can use our Low Carb Pizza Base – 190 g, ready to be topped and baked.

Ingredients for 1 pizza

Ingredient	Quantity
Low Carb Pizza Base	1 base (190 g)
Thick tomato purée (passata), no added sugar	50 g
Well-drained fiordilatte mozzarella	50 g
Well-drained tuna in brine	60 g
Red onion	20 g
Pitted black or Taggiasca olives	20 g
Extra virgin olive oil	4 g
Dried oregano	to taste
Fresh basil	a few leaves, optional
Black pepper	to taste, optional
Salt	to taste

⏱ Preparation time

Preparation: 10 minutes
Draining the mozzarella: at least 20 minutes
Baking the Low Carb Pizza Base: 10 minutes
Resting after baking: about 1 minute
Total active time: about 20 minutes
Servings: 1 pizza, for 1–2 people

How to make the Low Carb Tuna, Onion, and Olive Pizza

1. Prepare the mozzarella Cut the mozzarella into small cubes or strips. Place it in a strainer and let it drain for at least 20 minutes. Before using, gently pat it dry with paper towels. The mozzarella must be as dry as possible. 2. Prepare the tuna Drain the liquid from the tuna thoroughly. Transfer to paper towels and pat gently. Break it into pieces that are not too small, avoiding crumbling it completely. 3. Prepare the onion and olives Peel the onion and slice it very thinly. 20 g is sufficient for this recipe. Drain the olives, dry them, and cut them in half or into rounds. If they are particularly salty, you can rinse them quickly and dry them before using. 4. Preheat the oven Turn on the oven and bring it to a temperature between 220 and 240°C. If you are using a baking tray, let it heat up in the oven. The pizza should only be put in once the oven has reached the set temperature.

5. Prepare the tomato sauce Pour the tomato purée into a bowl. Add a very small amount of salt, a pinch of oregano, and about half of the extra virgin olive oil. Mix until you have a uniform sauce. If the purée is very liquid, reduce it briefly and let it cool. 6. Top the base Place the Low Carb Pizza Base on a sheet of parchment paper. Spread the tomato sauce in a thin layer, leaving a small border clear. Add the well-drained mozzarella, tuna, onion, and olives. Distribute the ingredients evenly, without piling them up in the center. Drizzle with the remaining extra virgin olive oil. 7. Bake the pizza Transfer the pizza to the hot tray and bake. Cook for 10 minutes, checking the pizza during the final minutes. The pizza is ready when the mozzarella is melted, the onion has softened slightly, and the crust has reached the desired consistency. If the onion tends to brown too quickly, cover it partially with a few pieces of mozzarella. 8. Final touches Take the pizza out of the oven and let it rest for about 1 minute. If you like, finish with some fresh basil leaves, a little more oregano, or a light dusting of black pepper. Serve immediately.

Chef's tips

• Drain both the tuna and mozzarella thoroughly.
• Use tuna in brine to better control the overall amount of oil.
• Do not shred the tuna too finely: slightly larger pieces remain juicier.
• Cut the onion very thinly to ensure it cooks in the allotted time.
• Do not exceed 20 g of onion: a larger amount would increase sweetness, moisture, and carbohydrates.
• Dry the olives well before distributing them on the pizza.
• Use very little salt, as the tuna, olives, mozzarella, and base are already flavorful.
• Use a thick tomato purée with no added sugar.
• Do not increase the amount of mozzarella: the other ingredients already make the topping substantial.
• For a crispier base, use a preheated baking tray.

How to choose tuna and olives

For this recipe, it is preferable to use tuna in brine with a simple ingredient list: tuna, water, and salt.

If you use tuna in oil, drain it very thoroughly and reduce or omit the 4 g of extra virgin olive oil provided in the recipe.

The olives should be simple, preserved in brine, and free from fillings or sweet dressings. Check the salt content, especially if using Taggiasca olives.

⚠️ Low carb warning

• Use tomato purée with no added sugar.
• Onion contains more carbohydrates than many other vegetables and must be used in the indicated amount.
• Avoid tuna seasoned with sauces, corn, legumes, or ready-made mixtures.
• Check that the olives contain no added sugar or fillings.
• Mozzarella provides a small amount of carbohydrates naturally found in milk.
• This recipe contains fish, gluten, and milk.
• Inclusion in a ketogenic diet depends on portion size and your overall meal plan.

Nutritional values — Complete dish

Values estimated based on a final weight of the baked pizza of approximately 370 g.

Average nutritional value	Per 100 g
Energy	158 kcal
Energy	661 kJ
Fat	5.4 g
of which saturates	2.2 g
Carbohydrates	3.0 g
of which sugars	1.0 g
Fibre	20.7 g
Protein	13.1 g
Salt	1.3 g

Nutritional note

Nutritional values are an estimate calculated for the complete recipe, considering:

• 1 Low Carb Pizza Base (190 g);
• 50 g tomato purée;
• 50 g fiordilatte mozzarella;
• 60 g drained tuna in brine;
• 20 g red onion;
• 20 g pitted olives;
• 4 g extra virgin olive oil;
• oregano and a minimal amount of salt;
• final cooked weight of approximately 370 g.

Values may vary based on the tuna, olives, mozzarella, tomato purée, amount of salt, and water lost during cooking.

Frequently asked questions

Can I use tuna in oil?

Yes. Drain and pat it dry thoroughly. In this case, it is preferable to omit or reduce the extra virgin olive oil called for in the recipe.

Can I omit the mozzarella?

Yes. You can prepare a red version with tomato, tuna, onion, and olives. By reducing the overall moisture, the crust may turn out slightly crispier.

Can I add capers?

Yes. You can add about 5g of well-rinsed and dried capers. Reduce the salt even further because olives, tuna, and capers are already very savory.

Can I pre-cook the onion?

Yes. You can soften it for 2–3 minutes in a pan with a little water. Before adding it to the pizza, let it cool and pat it dry well.

Which olives are most suitable?

You can use black olives, Taggiasca olives, or green olives. They must be pitted, well-drained, and free of any stuffings or sugary seasonings.

Is this pizza suitable for a ketogenic diet?

The base contains significantly fewer carbohydrates than a traditional base. However, compatibility with a ketogenic diet depends on the onion, the tomato puree, the portion size, and the specific meal plan followed.

Conclusion

The Low Carb Pizza with tuna, onion, and olives is a Mediterranean recipe with a bold flavor.

The secret is to use well-drained ingredients, a controlled amount of onion, and only a little tomato. This keeps the toppings balanced and prevents the base from absorbing too much moisture.

With the 190g Low Carb Pizza Base, you can prepare a rich and tasty pizza in about 20 minutes of actual prep time.

Learn more

If you want to read a complete guide on cooking, toppings, and using the ready-made base: Low carb pizza: how to prepare it with a ready-made base.

Discover our Low Carb Pizza Base – 190g and the Low Carb Pizza and Focaccia Bases collection.