Instant Pot Tuna and Egg-Stuffed Tomato Halves

Name: Instant Pot Tuna and Egg-Stuffed Tomato Halves
Prep time: 20 min
Cook time: 5 min
Total time: 25 min
Yield: 4 servings
Cuisine: Mediterranean
Ingredients: 4 medium (800 g) beefsteak tomatoes, ripe but firm, halved horizontally, seeds and excess pulp scooped out with a melon baller (reserve 2 tablespoons pulp); 5 oz (142 g) canned tuna in water, drained and flaked; 3 large eggs, hard-boiled, peeled and finely chopped; ⅓ cup (80 g) mayonnaise; 2 tablespoons (6 g) fresh dill, finely chopped; 1 tablespoon (15 ml) fresh lemon juice; sea salt; freshly ground black pepper; 1½ cups (355 ml) water; ¼ teaspoon (½ g) red pepper flakes (optional); 2 tablespoons (20 g) brined capers, rinsed and chopped (optional)

From the MyKitchenBank Kitchen

Tender beefsteak tomato halves filled with a bright tuna and hard-cooked egg salad, pressure-cooked in the Instant Pot to meld flavors while keeping the tomato skin intact. A Mediterranean-inspired dish that's protein-rich, light, and elegant enough for lunch or a light dinner.

Prep: 20 min
Cook: 5 min
Wait: 15 min
Total: 40 min
Makes: 4 servings (2 stuffed tomato halves per person)

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Steps

Before you start

Hard-boil the eggs in the Instant Pot first (if not using pre-cooked eggs), then drain and cool before peeling
Select firm, ripe beefsteak tomatoes of similar size so halves cook evenly
Have all filling ingredients measured and mixed before assembly to work efficiently

1
Prepare the tomato halves
- Wash the tomatoes thoroughly.
- Using a sharp knife, slice each tomato in half horizontally.
- With a melon baller or small spoon, gently scoop out the seeds and some of the pulp from each half, creating a shallow cavity about ½ inch (1.3 cm) deep.
- Be careful not to puncture the walls or bottom skin.
- Reserve 2 tablespoons of the scooped pulp for the filling and discard the rest.
- Lightly season the inside of each tomato half with a pinch of sea salt and black pepper.
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Ready when: Tomato halves have clean cavities and intact skins
Tip: Use a melon baller for even scooping; don't squeeze the tomato as it will bruise.
2
Make the filling
- In a small mixing bowl, combine the flaked tuna, chopped hard-boiled eggs, the reserved 2 tablespoons of tomato pulp, dill, lemon juice, and mayonnaise.
- Stir until well blended.
- Season to taste with sea salt and black pepper.
- If using capers and/or red pepper flakes, fold them in now.
- The filling should be moist but hold together.
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Ready when: Ingredients are evenly combined and moist
Tip: Don't overmix; fold gently to keep the egg pieces distinct and prevent a pasty texture.
3
Fill the tomato halves
- Spoon the tuna mixture evenly into the cavity of each tomato half, mounding it slightly (about 3 tablespoons per half).
- You should have about 3 tablespoons of filling per tomato half.
- Arrange the filled tomatoes on a clean cutting board, ready to transfer to the Instant Pot.
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Ready when: All 8 tomato halves are evenly and generously filled
Tip: Work quickly so the tomato flesh doesn't weep; chill the filling for 30 minutes beforehand if your kitchen is very warm.
4
Set up the Instant Pot
- Pour 1½ cups (355 ml) of water into the Instant Pot insert.
- Place the trivet or steamer rack inside, ensuring it sits above the water level.
- Arrange the filled tomato halves on the trivet in a single layer, cut-side up, so they don't touch each other.
- They should fit snugly but not be cramped; if your Instant Pot is small, you may need to cook them in two batches.
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Ready when: Tomatoes are positioned upright and stable on the trivet
Tip: Use a trivet to keep tomatoes above the boiling water; direct contact will make them fall apart.
5
Pressure cook the tomatoes
- Secure the Instant Pot lid and set the valve to 'sealing'.
- Press the 'Manual' or 'Pressure Cook' button and set the timer for 2 minutes at high pressure (118°C / 10 psi).
- The pressure will build for about 8–10 minutes before cooking begins.
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Tip: Don't open the lid early; the tomatoes need gentle, controlled heat to stay intact.
6
Release pressure and cool slightly
- When the timer beeps, switch the valve to 'venting' to release pressure quickly (about 2–3 minutes).
- Wait until all steam has escaped, then carefully open the lid away from you.
- The tomatoes should be warm but still hold their shape.
- Let them rest in the pot for 1 minute, then carefully transfer them to a serving platter using tongs or a slotted spoon.
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Ready when: Tomato skin is slightly softened but not collapsing; filling is heated through
Tip: Quick venting cools the tomatoes just enough to handle safely while keeping the filling warm.
7
Finish and serveOven 300°F / 150°C
- Transfer the cooked tomato halves to a serving platter or individual plates.
- If the filling has cooled, you can serve at room temperature or gently reheat in a 300°F (150°C) oven for 5 minutes.
- Garnish with extra fresh dill, a light sprinkle of red pepper flakes, or a few brined capers if desired.
- Serve immediately.
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Ready when: Tomato halves are warm or at desired serving temperature
Tip: This dish is best served shortly after cooking while the tomato is still tender; reheating beyond 5 minutes may soften it too much.

Good to know

Tips

Hard-boil the eggs in the Instant Pot first for convenience: add 1 cup water, place eggs on the trivet, pressure cook at high for 5 minutes, then quick-release. This means they cook together with the tomatoes in a complete meal.
To prevent watery filling, pat the hollowed tomato insides dry with a paper towel before filling; this absorbs any excess liquid that seeps from the flesh.
For a cold presentation, chill the cooked tomato halves completely in the refrigerator and serve with a dollop of crème fraîche or a drizzle of good olive oil for extra richness.
This recipe scales well: use 2 tomatoes per person or adjust water in the Instant Pot slightly (1½ cups for up to 8 tomato halves arranged in layers). Don't increase pressure cook time if stacking; the top layer will cook as quickly as the bottom.

Make ahead

The tuna-egg filling can be prepared up to 6 hours ahead and chilled. Assemble and fill the tomato halves no more than 30 minutes before cooking to prevent them from weeping excess liquid.

Storage & reheating

Store leftovers in an airtight container in the refrigerator for up to 2 days. The tomatoes will soften further upon storage. Reheat gently in a 300°F (150°C) oven for 5–7 minutes, or eat chilled as a salad. Do not freeze; the tomato texture will break down when thawed.

Substitutions

canned tuna in water → canned salmon or fresh flaked white fish (cod or halibut). Salmon will add a richer flavor; fresh fish must be cooked first. Use the same weight.
mayonnaise → Greek yogurt or sour cream. Use the same amount for a tangier, lighter filling with less fat. Mix well to avoid overmixing the eggs.
fresh dill, finely chopped → fresh tarragon or basil. Tarragon adds a subtle anise note; basil brings Italian flavor. Use the same weight.
beefsteak tomatoes, ripe but firm → large heirloom tomatoes (Roma, Brandywine, or Cherokee Purple). Choose similarly sized tomatoes so they cook evenly. Very soft or overripe tomatoes may collapse under pressure.