Silakkalaatikko Baltic Herring Casserole

By AislePrompt Editorial · Published 2026-10-09 · Updated 2026-10-09

Layers of thin-sliced potato, butter-softened onion and fresh Baltic herring fillets baked in a savory egg-milk custard until golden on top. This Finnish-inspired seafood recipe, ready in about 95 minutes, pairs waxy potatoes, peeled and thinly sliced, yellow onions, thinly sliced, butter for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 430 calories and feeds 6, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 600 g fresh Baltic herring fillets, butterflied
• 1 kg waxy potatoes, peeled and thinly sliced
• 2 yellow onions, thinly sliced
• 3 tbsp, plus extra for the dish butter
• 3 eggs
• 500 ml whole milk
• 2 tsp, divided salt
• 1/2 tsp white pepper
• 1/2 tsp whole allspice, crushed
• 3 tbsp fresh dill, chopped
• 3 tbsp dry rye breadcrumbs

The 9x13 baking dish we’d bake this in → Best Bakeware for 2026: Top Picks + Buying Guide

Instructions

1. Step 1: Heat the oven to 200°C (390°F) and butter a 2-liter baking dish.
2. Step 2: Cook the onions in 1 tbsp butter over medium-low heat for 8 minutes, until soft and lightly golden.
3. Step 3: Put a third of the potato slices in the dish and season with salt and pepper. Add half the herring fillets, skin side down, then half the onions, half the allspice and some dill.
4. Step 4: Repeat the layers, finishing with a final layer of potatoes.
5. Step 5: Whisk the eggs with the milk and 1 tsp salt and pour the mixture evenly over the casserole.
6. Step 6: Scatter the rye breadcrumbs over the top and dot with the remaining butter.
7. Step 7: Bake for 60–70 minutes, until the potatoes are tender and the top is golden. Let it rest for 10 minutes, then serve with melted butter and beetroot salad.