Peel the pears, cut into beautiful slices, sprinkle with lemon juice. In a large bowl, beat the softened butter until creamy and, without ceasing, beat, add sugar.
Beat in eggs one at a time, mixing well each time. When the mass becomes homogeneous, pour in grappa, mix. In a separate bowl, mix the sifted flour, cinnamon and baking powder. Carefully add flour mixture to butter-egg mixture.
Grease a 22 cm diameter mold with butter, sprinkle with flour and pour the dough into it. Put the pears nicely on top and bake the cake in an oven preheated to 180 ° C for 45 minutes. This cake can be served warm or chilled.