Cook onions in butter, olive oil & salt until golden & jammy. Remove.
Brown & season beef. Add garlic, tomato paste, Worcestershire, thyme, salt & pepper.
Return onions, add flour & cook for 1 minute.
Add stock & parmesan rind. Simmer 5 minutes, add spaghetti & cook until tender. Remove rind, stir through butter & vinegar.
Brown butter for the cream. Stir through cream, Dijon, parmesan & pepper.
For the rolls, cook milk & flour into a thick paste. Cool.
Combine flour, yeast, sugar & salt. Add tangzhong, milk & egg. Mix into a dough, knead in butter until smooth.
Proof 1–2 hours. Divide into 7 balls, rest 15 minutes, place in a greased dish & proof 30–45 minutes.
Brush with milk & bake at 180°C for 15–18 minutes.
Brush with garlic butter, top with Gruyère & grill until golden.
Spoon parmesan cream onto a plate, top with bolognese & serve with the rolls.
