Vegan Tuna Casserole Recipe

A comforting, creamy casserole with flaky hearts of palm "tuna," tender pasta, and a golden breadcrumb topping that delivers all the nostalgic flavor without any seafood.
Difficulty:
Beginner
Prep Time:
20 mins
Cook Time:
30 mins
Serves:
6 servings
An overhead shot of a bubbling vegan tuna casserole in a rustic ceramic baking dish, showcasing the golden-brown breadcrumb topping with flecks of herbs. Steam rises gently as a serving spoon lifts a portion, revealing the creamy interior studded with flaky hearts of palm, peas, and shell pasta. Soft natural light highlights the contrasting textures between the crisp topping and creamy filling. The dish sits on a worn wooden table beside scattered fresh herbs and lemon wedges, with cozy linen napkins and simple ceramic plates suggesting a wholesome family dinner setting.

Ingredients

<ul class="ingredients-main-list"><li class="ingredients-single-item">300g shell pasta (or any medium pasta shape)</li><li class="ingredients-single-item">2 cans (400g total) hearts of palm, drained and flaked with a fork</li><li class="ingredients-single-item">150g frozen peas</li><li class="ingredients-single-item">1 medium onion, finely diced</li><li class="ingredients-single-item">3 garlic cloves, minced</li><li class="ingredients-single-item">250g cashews, soaked for 4 hours or quick-soaked in hot water for 30 minutes</li><li class="ingredients-single-item">500ml vegetable stock</li><li class="ingredients-single-item">60ml nutritional yeast</li><li class="ingredients-single-item">2 tbsp lemon juice</li><li class="ingredients-single-item">1 tbsp dijon mustard</li><li class="ingredients-single-item">1 tsp dried dill (or 1 tbsp fresh)</li><li class="ingredients-single-item">1 tsp dried thyme</li><li class="ingredients-single-item">1 sheet of nori seaweed, crumbled (optional for seafood flavor)</li><li class="ingredients-single-item">2 tbsp capers, drained and roughly chopped</li><li class="ingredients-single-item">2 tbsp olive oil</li><li class="ingredients-single-item">100g panko breadcrumbs</li><li class="ingredients-single-item">2 tbsp vegan butter, melted</li><li class="ingredients-single-item">Salt and black pepper to taste</li></ul>

Equipment

<ul class="equipment-main-list"><li class="equipment-single-item">High-speed blender</li><li class="equipment-single-item">25cm (10-inch) casserole dish</li><li class="equipment-single-item">Fork (for flaking hearts of palm)</li></ul>
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Directions

<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Preheat your oven to 190°C (375°F) and lightly grease a 25cm (10-inch) casserole dish. Begin cooking your pasta in salted water until al dente, about 2 minutes less than package instructions. The pasta will continue cooking in the oven, so slightly undercooking it now prevents mushiness later.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>While the pasta cooks, prepare your "tuna" by draining the hearts of palm and using a fork to gently flake them into shreds that resemble tuna texture. Don't over-shred – the varied texture is part of what makes this substitute convincing.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>In a large saucepan, heat the olive oil over medium heat. Add the diced onion and cook for 5-6 minutes until translucent. Add the garlic and cook for another 30 seconds until fragrant. The slow cooking of the onions develops a sweet flavor base that enriches the final dish.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Make the cashew cream sauce by placing the drained soaked cashews, vegetable stock, nutritional yeast, lemon juice, dijon mustard, dried dill, dried thyme, and crumbled nori (if using) in a high-speed blender. Blend until completely smooth and creamy, about 2 minutes. This cashew base creates a rich, velvety sauce that rivals traditional dairy-based versions.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Pour the cashew cream mixture into the saucepan with the onions and garlic. Stir well and bring to a gentle simmer for 3-4 minutes until slightly thickened. The sauce should coat the back of a spoon but still remain pourable.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Drain the cooked pasta and add it to a large mixing bowl. Add the flaked hearts of palm, frozen peas (no need to thaw), capers, and the cashew cream sauce. Stir gently to combine, being careful not to break up the delicate "tuna" flakes too much. Season to taste with salt and black pepper – be generous with the seasoning as it really lifts the flavor profile.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Transfer the mixture to your prepared casserole dish, spreading it evenly. In a small bowl, combine the panko breadcrumbs with melted vegan butter and a pinch of salt, then sprinkle this mixture evenly over the top of the casserole. The breadcrumbs will create a deliciously crispy contrast to the creamy filling.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Bake in the preheated oven for 25-30 minutes, until the top is golden brown and the edges are bubbling. If the top browns too quickly, loosely cover with foil and continue baking. The casserole needs this time to allow the flavors to meld and develop that classic baked comfort food taste.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>Remove from the oven and let stand for 5-10 minutes before serving. This resting period allows the casserole to set slightly, making it easier to serve while still maintaining its heat. Garnish with additional fresh herbs if desired and enjoy the nostalgic comfort of tuna casserole, made completely plant-based!</li></ol>

Nutrition Facts (per serving)

🍽️ Serving Size: 1 serving
🔥 Calories: 320 calories
🥑 Fat: 14 g
🧈 Saturated Fat: 2 g
🍞 Carbohydrates: 42 g
🍭 Sugar: 3 g
🍗 Protein: 9 g
🫀 Cholesterol: 0 mg
🧂 Sodium: 380 mg

Chef’s Notes

A few helpful details for making this recipe.

Can hearts of palm really mimic the texture of tuna in a casserole?

Yes! Hearts of palm have a surprisingly similar flaky texture to tuna when gently pulled apart with a fork. When combined with the seafood flavours from nori and capers, plus the creamy sauce, most people are amazed at how convincingly it replicates the texture and taste of traditional tuna casserole.

What's the best way to achieve a rich, creamy sauce without dairy?

The secret to a luxurious dairy-free sauce lies in properly soaked cashews blended with vegetable stock until completely smooth. Nutritional yeast adds cheesy flavour, while lemon juice and dijon mustard provide tanginess. Simmering the sauce briefly helps it thicken to the perfect consistency for coating pasta.

How can I make this plant-based casserole more "fishy" without using actual seafood?

To enhance the seafood flavour, incorporate crumbled nori seaweed sheets, a splash of vegan Worcestershire sauce, or a teaspoon of miso paste. Adding extra capers or a small amount of dulse flakes (a type of seaweed) will further amplify the oceanic notes without any actual fish.

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