Pre-heat salamander style grill or top element of oven to a high heat.
Place cassia, star anise, cloves, cardamom, onion and ginger in an ovenproof pan or baking tray and grill 3-4 minutes until fragrant. Remove. Turn off grill.
Place grilled spices, onion and ginger in a large stockpot. Add veal bones, brisket and enough cold water to cover, bring to a slow boil.
Simmer two hours, skimming the surface of any fat or scum as necessary, then remove brisket and store, covered and refrigerated until needed.
Continue cooking stock a further 2 hours, skimming as necessary. Season with fish sauce, sea salt and sugar to taste, using the above quantities as a guide.
Strain stock and discard bones, onion, ginger and spices. Cool and store refrigerated until needed or strain stock to a clean pot and bring back to a simmer, ready to serve.
To serve, place sprouts, herbs, chillies and lime wedges in little bunches around a serving plate, place on table for guests to add to their pho as desired.
Bring a pot of lightly salted water to a rapid boil. Using a small blanching basket or chinois, blanch a small handful of noodles and spring onions for each person. Transfer each portion to individual serving bowls (pho is one of the few Vietnamese dishes not shared, with each diner receiving their own bowl).
Slice reserved brisket thinly and place atop noodles. If using, add 20-30g thinly sliced raw beef per portion. Ladle hot stock over beef and noodles (the heat of the stock will cook the finely sliced raw meat). Garnish with chopped coriander and chives, season lightly with pepper.
Serve hot portions to each guest, accompanied by Asian soup spoons and chopsticks (for the handling and choice of the fresh herbs).