
Step 1 · Brown the Beef
Heat the oil in a large, deep pan over high heat. Add the beef and cook for 5 minutes, breaking it up, until browned.
Step 2 · Cook the Vegetables
Add the mushrooms and onion. Cook for 4 minutes, stirring often, until the mushrooms soften. Add the garlic and stir for 30 seconds.
Step 3 · Simmer the Orzo
Add the orzo, stock or water and salt. Bring to a boil, then simmer uncovered for 10 to 12 minutes, stirring frequently, until the orzo is tender. Add a splash of hot water if needed.
Step 4 · Add Mustard and Peas
Stir in the mustard and peas and cook for 2 minutes.
Step 5 · Finish and Serve
Remove from the heat and stir in the sour cream or crème fraîche. Taste before adding more salt, scatter with parsley and serve. Offer black pepper at the table for adults.