Finely chop the shallot, slice the mushrooms, cut the Mostbröckli into strips and dice the pear. Heat the butter in a fondue pot, briefly sauté the shallot, add the mushrooms, Mostbröckli and pear, cook for approx. 3 mins. Remove, keep warm.
Coarsely grate the cheese and add to the fondue pot, mix in the cornflour. Pour in the wine and lemon juice, bring to the boil while stirring, reduce the heat, continue to simmer and stir until the cheese has melted. Add the Williams pear schnapps, season to taste. Serve the fondue immediately, gradually incorporate the warm mixture into the fondue.