Koji-Cured Pineapple Steak with Béarnaise
A thick slab of pineapple inoculated with koji rice for three days develops a savoury crust and a dense, meaty chew. Seared in butter and served with a classic béarnaise, it is the most convincing vegetable steak our kitchen has made, and it comes from a fruit.
- 1 ripe but firm pineapple, peeled and cored, cut into four 2 cm thick slabs
- 40 g dried koji rice, ground to a powder
- 40 g butter, plus more for the sauce
- For the béarnaise: 3 tablespoons white wine vinegar
- 1 shallot, chopped
- A handful of tarragon, leaves and stalks separated
- 3 egg yolks
- 200 g butter, melted and warm
- Salt, lemon juice
- Dust the pineapple slabs all over with the ground koji. Set on a rack over a tray, uncovered, in the fridge for 72 hours.
- Rinse the slabs briefly, pat very dry, and leave at room temperature for 30 minutes.
- For the sauce, reduce the vinegar, shallot and tarragon stalks to a tablespoon. Strain into a bowl set over barely simmering water, whisk in the yolks until thick, then whisk in the warm butter in a thin stream. Season, add chopped tarragon leaves and lemon.
- Heat a heavy pan until very hot, add the butter, and sear the slabs for 2 minutes each side until deeply browned. Rest 3 minutes.
- Serve the slabs with the béarnaise and chips.
Koji is the mould that makes miso, soy sauce and sake possible: Aspergillus oryzae, grown on rice, whose enzymes break proteins and starches into amino acids and sugars. Applied to meat as a dry rub of koji rice, it is used in ambitious kitchens to age a steak in 48 hours instead of 30 days. Our kitchen turned the question around: what does koji do to something that has almost no protein and a great deal of sugar?
On pineapple, the answer is transformation. Pineapple carries its own enzyme, bromelain, which is why it tenderises meat. Dusted with ground koji rice and left in the fridge for 72 hours, a two-centimetre slab of pineapple loses water, develops a faint white bloom, and its surface sugars begin to convert into a savoury, almost soy-like layer. Rinsed, dried and seared hard in butter, it browns like meat, because the Maillard reaction needs sugars and amino acids and now it has both. The interior stays juicy but firm, with a chew closer to swordfish than fruit.
The numbers
- Cure: 30 g of ground dried koji rice per 500 g of pineapple, 72 hours at 4 C, uncovered on a rack so the surface dries.
- Weight loss: about 18 percent. The slabs shrink and darken; that is what you want.
- Sear: 2 minutes per side in foaming butter at high heat, then rest for 3 minutes. Any longer and the sugars burn before the centre warms.
Why béarnaise
Because a steak deserves one. The tarragon and shallot reduction, the egg yolks, the butter: béarnaise was designed to meet the char of grilled beef with acidity and herb, and it does precisely the same work against a seared pineapple, whose sweetness now sits behind a savoury crust. Serve with thin chips, a glass of Beaujolais, and no announcement. Let them find out.
