Heat oil in non-stick pan. Cook onion for 5 minutes, then add beef mince and stir until done. Add tomatoes and stir the mixture for 2 minutes. Add Knorr Tomato Sauce and water to the mixture.
Cook on low flame and stir occasionally for 10 minutes. Then add chopped black olives, stir the mixture then set it aside to cool.
Stuff cannelloni tubes with bolognese sauce and put them aside.
Mix milk with the contents of Knorr Bechamel Mix sachet and stir till boils. Place it on low flame till thickened.
Cover tray with Knorr Bechamel Sauce. Place cannelloni tubes over bechamel sauce and pour the remaining sauce on the surface of the tray.
Sprinkle the surface of the tray with cheese. Bake in pre-heated oven at 220 degrees for 20-25 minutes or until it turns gold.