The exact invention of sandwich where pressed some meat between two slice of bread possibly goes to John Montagu, the fourth Earl of Sandwich but it is still the subject of debate. A rumor in a contemporary travel book called Tour to London by Pierre Jean Grosley formed the popular myth that bread and meat sustained Lord Sandwich at the gambling table and this was generally served to the navy, to politics and the arts mean the first sandwich was more likely to have been consumed at his desk. However the fast-food giant McDonald’s has set its sights on his invention by filling patents in Europe and the US that claim the “method and apparatus for making a sandwich” as its intellectual property.
Patent application WO2006068865 relates to the “pre-assembly of sandwich components and preparation of different parts of the same sandwich” ( it only mentions generic sandwich making ‘tools,’ rather than any specific machine) . It covers the process for toasting of a bread component” and heating a “meat and/or cheese filling”. The company says they’ve invented a way to add garnishes and condiments using a “sandwich assembly tool”.
So until the patent is rejected don’t follow the same process because you will be charged for infringing the patent. 