The charcuterie programme alone runs to a balotina of black rooster, wild boar head, and pistachio-studded pork belly. Elsewhere: Bedon trout smoked over apple wood with roe and rye bread, raw wagyu tongue sliced tableside, and a rabbit rillette that applies classical French technique to Spanish product. The cellar holds around 500 references, centred on France, above all Burgundy, and Piedmont, with sherries from Jerez and Sanlúcar on the list too. The approach favours sparseness and precision over flourish.

A June 2026 meal shows where the trilogies go now: a house kombucha to start, a riff on cocido with pork and Lalín, the charcuterie board, Chipiona red mullet with an amazake tempura, a koji carrot, a Galway oyster served first natural and then with potato and giant beans, quail with Moroccan preserved lemon, koshihikari rice with morcilla, espardeña with pork-skin 'noodles', Padrón peppers with garum, a monkfish bouillabaisse, a shot hen pheasant, and a sake-kasu dairy dessert. The room keeps the ritual of a proper casa de comidas, with tablecloths and linen napkins.

Jorge Muñoz and Sara Peral opened OSA in mid-March 2023 in a small two-storey chalet, once a private home, in the Colonia del Manzanares, beside the river on the Casa de Campo side. The chefs like to say the meal starts before you arrive, on the walk along the riverbank.

In the same year it opened, OSA won its Michelin star in the 2024 guide, announced in November 2023, and it holds two Repsol Soles. Madrid Fusión named Muñoz and Peral its Revelation Chefs in 2024. OAD ranked OSA 33rd in its Europe Top Restaurants list for 2025 and 30th in 2026. Peral left at the start of 2026, and Muñoz has led the restaurant since.

Jorge Muñoz started in kitchens before hotel school, then went through the Escuela de Hostelería Lago, El Pedrusco, La Tasquita de Enfrente in Madrid and Mugaritz, and created Picones de María before leaving to open OSA with Sara Peral, who had cooked at Mugaritz, DiverXO and Coque. The two summed up their cooking as Spanish produce, French technique and Japanese sensibility, with classical methods and very few ingredients per plate, and 'less is more' remains Muñoz's rule now that he runs the kitchen on his own, following Peral's departure at the start of 2026.

OSA builds its menus around what the kitchen calls product trilogies, three elements named on the menu, such as rillettes, rabbit and Le Mans, or trout, Bedón and apple wood. The summer 2026 line-up runs to three menus: the XL at €200 for 18 to 20 courses, the OSA menu at €170 for 13 to 14 courses, and the five-course osa|terraza, served on the terrace, from €80.

Whichever menu you pick is served to the whole table, and there is no vegetarian or vegan menu, so tell the restaurant about allergies when you book.

A dedicated aging chamber holds the kitchen's own charcuterie and hung game: backbones, heads, trotters, shoulders, ducks, quail and zampone, left for anywhere from two to five weeks depending on the cut. That programme is behind charcuterie such as the black-rooster ballotine, the wild boar head and the pistachio-studded pork belly.

Upstairs, the cellar holds around 500 references and 3,600 bottles, with France, especially Burgundy, and Piedmont at its core.

There are two sittings at each service: dinner at 20:30 or 21:15 from Tuesday to Saturday, and lunch at 13:30 or 14:15 from Wednesday to Saturday. OSA is closed on Sunday and Monday. Tables are booked through the widget on OSA's own site, for one to six people, and each booking carries its own cancellation policy. The restaurant recommends it for children aged 12 and over, has no high chairs, does not take pushchairs, and admits only guide dogs.