Pot-roast beef with French onion gravy

Heat 28g olive oil in a large heavy pot over medium-high heat. Season the 1000g beef with salt and pepper, then brown all sides until deeply caramelized, about 10 minutes total. Remove and set aside.

Reduce heat to medium. Add 500g sliced onions to the pot and cook gently without color for 8 minutes, stirring occasionally.

Stir in 1g celery, 4g muscovado sugar, and 5g flour. Cook for 2 minutes, stirring constantly to coat the onions.