Refrigerate the ricotta cheese in a strainer overnight so that the excess moisture is removed.
In a mixing bowl, blend the ricotta cheese and 1 1/2 tablespoons sugar with a hand mixer until it becomes a velvety consistency. In a separate bowl, whip the cream with 1/2 tablespoon of sugar. Gently fold in the whipped cream into the ricotta mixture along with the bittersweet chocolate. Spread the filling into the piecrust and refrigerate.
In a saucepan, heat the remaining 1 1/2 tablespoons sugar and 2 cups of water. Once the sugar has dissolved, add the pears and gently simmer until soft when pierced with a knife. Remove the pears from the pan and let cool. Cut the pears into slices and fan the slices on top of the pie filling, until the surface of the pie is covered. Fill in the gaps with extra pieces of pear, if necessary.
In another saucepan, heat the remaining 1 cup water and apricot jam. Stir and cook until the jelly is liquefied, so that it can be used as a glaze. Spread the apricot glaze over the pears and let the pie rest in the refrigerator for 4 hours before serving.