Two kinds of Danish open sandwich on dark rye: smoked sprats with radish, chives and a bright raw egg yolk, and flaked smoked trout over horseradish cream, cucumber and dill

Smoked Trout and Sprat Smørrebrød on Buttered Rye

September 28, 2026

A tin of smoked trout and a tin of smoked sprats arrive already smoked and already cooked. What is left is the bread and the partners, and Danish smørrebrød supplies both. Smørrebrød, the Danish open sandwich, is dense rye bread buttered to the edges and topped with one main thing and a few sharp things around it. This recipe makes two kinds. The sprats go on the way Bornholm serves its smoked herring: radish, chives, onion and a raw egg yolk as the sauce. The trout goes over horseradish cream and cucumber, which suits a milder, flakier fish. One of each on the plate is the quickest way to learn what each tin is for.

On Bornholm, the Baltic island known for its smokehouses, the famous version is Sol over Gudhjem, "sun over Gudhjem." VisitDenmark describes it as smoked herring, raw egg yolk, chives, and radish, served on freshly baked rye bread. The island's first smokehouse opened in 1866, and the fish there is smoked over alder wood. Smoked sprats from a tin are small, oily Baltic fish and close relatives of the herring, and they suit the same bread.

Ingredients, for four

8 thin slices dense Danish rye bread (rugbrød), about 1 cm thick
40 g (3 tablespoons) salted butter, soft
1 tin (100 g) smoked Baltic sprats in oil, such as Fangst Brisling No. 2 (shop Fangst Brisling No. 2) or Fangst Brisling No. 1, smoked with heather and chamomile (shop Fangst Brisling No. 1)
1 tin (about 110 g) smoked trout in oil, such as Fangst Regnbue Ørred with juniper and lemon thyme (shop Fangst Regnbue Ørred) or José Gourmet smoked trout fillets (shop José Gourmet smoked trout fillets)
4 pasteurized egg yolks, or 2 hard-cooked eggs, sliced
4 radishes, sliced paper thin
1/4 small red onion, finely diced
1 small bunch chives, finely cut
80 g (1/3 cup) crème fraîche
2 teaspoons prepared horseradish, or 1 tablespoon Edmond Fallot horseradish Dijon (shop Edmond Fallot horseradish Dijon) for a milder, mustardy cream
1 lemon, for zest and juice
1/2 small cucumber, sliced thin
A few sprigs dill
Flaky sea salt, such as Saltverk (shop Saltverk flaky sea salt), and black pepper

Method

Keep the tins in the cupboard. Keep both tins at room temperature, not in the refrigerator, so the oil is loose over the fish when the lid comes off.
Make the horseradish cream. Stir the crème fraîche with the horseradish, the zest of half the lemon, 1 teaspoon of lemon juice and a pinch of salt. Chill it while you prepare the rest.
Prepare the sharp things. Toss the cucumber slices with a pinch of salt, leave them for 10 minutes, then pat them dry. Slice the radishes, dice the onion and cut the chives.
Butter the bread. Butter all 8 slices of rye right to the edges, thin but complete, so no bread shows. The butter seals the bread against the wet toppings and carries the salt.
Build the trout slices. Spread 4 slices with the horseradish cream, shingle the cucumber over it, break the trout into large flakes on top and finish with dill, pepper and a few drops of lemon juice.
Build the sprat slices. Lay 4 to 6 sprats side by side on each of the other 4 slices. Scatter over the radish, onion and chives, press a small hollow in the center and set a pasteurized yolk in it, or lay on sliced hard-cooked egg. Finish with flaky salt and pepper.
Serve. Serve at once, one of each per person, with a knife and fork. Break the yolk at the table so it runs over the fish as the sauce.

Why nothing here is cooked

Smoked fish sold in a sealed tin in the United States falls under the federal rules for thermally processed low-acid foods in hermetically sealed containers, which require heat processing to commercial sterility. The fish is smoked first and then heat-processed for the tin, so it is already fully cooked when the tin is opened. The recipe asks one thing of the tin: that it be at room temperature. Fangst's own storage note for its trout reads "Cool or at room temperature. After opening in refrigerator." A tin kept in the cupboard is ready to serve the moment it is opened, with the oil loose over the fish.

The yolk, safely

The raw yolk is the traditional "sun," and it is the sauce: broken at the table, it coats the sprats and the rye. For any dish served with raw egg, the FDA advises using shell eggs that have been treated to destroy Salmonella, by pasteurization or another approved method, or pasteurized egg products. Pasteurized-in-shell eggs are usually labeled as treated on the carton. If none are available, sliced hard-cooked egg keeps the richness without the runny sauce.

Colorado State University Extension notes that hard-cooked eggs take longer at altitude, and a "3-minute" egg may take 5 minutes at 5,000 feet, because water boils at about 203°F at that height. At Denver's elevation, cook the eggs longer than your sea-level time, then chill them in cold water before peeling. The Cooking at Altitude guide covers the rest of the stove.

Which tin on which slice

The two sandwiches are not interchangeable, and the reason is the fish. Sprats are small, whole, oily and strongly smoked, so they want sharp, raw partners and something rich to bind them. Trout comes in larger, softer flakes with gentler smoke, so it wants a creamy base with some heat and a cool crunch on top.

Tin	What it brings	What goes with it on the rye
Smoked sprats (brisling)	Whole small fish, oily, strongly smoked; Fangst's are Baltic Sea Sprattus sprattus in cold-pressed rapeseed oil	Radish, raw onion, chives and an egg yolk: sharpness and crunch, then richness to bind
Smoked trout	Large, soft flakes and gentler smoke; Fangst's Danish trout is seasoned with juniper and lemon thyme	Horseradish cream, salted cucumber, dill and lemon: heat and cool crunch under a mild fish
Smoked herring (the original)	The fish Bornholm uses for Sol over Gudhjem; meatier than sprats	Everything on the sprat slice; for herring from a tin, Fangst Sild No. 1 (shop Fangst Sild No. 1) is Norwegian Sea herring smoked with white pepper and ramson

Why it went wrong

Symptom	Cause	Fix
Soggy bread	Bare patches of rye, or wet cucumber	Butter to every edge; salt and pat the cucumber dry; assemble just before serving
Oil set firm around the fish	Tins opened cold from the refrigerator	Keep unopened tins in the cupboard and serve at room temperature
Sprat slice lacks contrast	Nothing sharp to cut the oil	More radish and raw onion, and a squeeze of lemon at the table
Trout disappears	Too much horseradish cream, or the fish mashed into it	Spread the cream thin and lay the trout on top in large flakes
Bread breaks under the knife	Slices cut too thick or too thin	About 1 cm; dense rye holds up to a knife and fork at that thickness

Notes and variations

The bread. Danish rugbrød is dense, dark and sour, and it stands up to butter, oil and yolk without going soft. Any dense whole rye works. Crisp rye or a good flatbread turns this into something to pass around with drinks, and Crackers: The Complete Guide covers which ones hold up to oily fish.

The oil. A spoon of oil from the trout tin stirred into the horseradish cream carries the juniper into it. The rest has more uses in the guide to the oil left in a tin of fish.

Leftovers. An opened tin moves to the refrigerator in a covered container, and the guide to how long tinned fish lasts after opening has the timings.

Further reading. For sardines, the other oily fish in the tin aisle, see the guide to serving sardines straight from the tin. Fangst, the Danish company behind the sprats, trout and herring here, is profiled in the Fangst producer guide, and more Danish food is in the New Nordic Danish pantry guide. For the plate as written: Fangst Brisling No. 1 (shop Fangst Brisling No. 1), Fangst Regnbue Ørred (shop Fangst Regnbue Ørred), Edmond Fallot horseradish Dijon (shop Edmond Fallot horseradish Dijon) and Saltverk flaky sea salt (shop Saltverk flaky sea salt), all shipped nationwide from theambrosianpantry.com.