Use a 26cm springform tin. Lightly grease tin. For the pastry, place the butter, flour, sugar, egg yolk and rum or apple juice in a bowl; mix lightly. Knead ingredients together by hand or use the dough hooks of an electric mixer.
Flour hands and knead dough on a floured board until shiny. Shape into a smooth ball and wrap in cling wrap. Chill for 30 minutes.
Meanwhile, peel, quarter and core the apples and 2 pears and cut into pieces.
Place apple and pear pieces in a saucepan with the lemon juice, water or pear juice, ground cinnamon and ground cloves.
Cover the pan; simmer mixture over low heat until fruit is soft. Cook, uncovered, for 15 minutes until fruit has reduced to a purée. Remove pan from heat. Leave the mixture to cool.
Preheat oven to 180 degrees C. Roll pastry into a round to fit the base and side of the tin. Spread the fruit purée over the pastry base and pre-bake for about 20 minutes.
Meanwhile, peel, quarter and core the remaining pears and cut into neat slices. Arrange over the puréed fruit in the pastry case. Sprinkle the pistachio nuts over the top. Bake for a further 15 minutes. Cool before serving.