On a lightly floured work surface, roll 1 disk of dough to 1/8 inch thick. Fit into a 9-inch deep-dish pie plate. Trim edges flush with rim. Refrigerate for 1 hour.
On a piece of lightly floured parchment paper, roll out remaining disk of dough to 1/8 inch thick. Top with an inverted 9-inch pie plate or a cake ring, and gently press to make a light indentation (this will be your guide for cutting the lattice to fit the pie). Using a 3/4-inch square cutter, cut a lattice pattern out of the round, leaving at least 1/2 inch between cutouts and edge of round. Transfer squares to a parchment-lined baking sheet. To make partial squares where the lattice meets the rounded edge, make a very light indentation with the cutter, then cut out the portion of the square that is inside the round with a knife. Using a paring knife or a pizza cutter, cut out the round, leaving an additional 1/2 inch of dough beyond the marked circle. Reroll scraps, and cut out as many additional squares as possible. Transfer parchment with the lattice top to a baking sheet. Refrigerate lattice top and squares for 1 hour.
Preheat oven to 375 degrees, with racks in middle and lower positions. Peel, halve, and core pears. Very thinly slice 3 pears lengthwise, and cut remaining 2 pears into 8 wedges each.
Toss together pears, cranberries, sugar, cornstarch, and salt in a large bowl. Using the tip of a paring knife, scrape vanilla seeds over pear mixture, and toss until seeds have been evenly incorporated. Pour filling into piecrust, gently pressing to make it as level as possible. Dot filling with butter.
To make egg wash, whisk together egg yolk and cream in a small bowl. Lightly brush edge of piecrust with egg wash. Remove lattice crust and squares from refrigerator. Gently place another baking sheet on top of lattice, and carefully invert. Slide lattice on top of filling, and remove parchment. Gently press edges of crust to seal, trimming edges of lattice if necessary.
Lightly brush lattice with egg wash.
Arrange dough squares around edge of pie, overlapping them slightly. Lightly brush top of each square with egg wash as you work to help them adhere.
Place a foil-lined baking sheet on lower oven rack to catch any juices. Place pie on middle rack, and bake until crust is golden brown and juices are bubbling gently, 90 to 100 minutes. Tent with foil if crust browns too quickly. Let pie cool on a wire rack for 5 minutes.
Meanwhile, heat preserves in a saucepan over medium heat until warm. Puree in a food processor until smooth. Press through a fine sieve into a bowl or another saucepan, and reheat if necessary. Brush warm pie with a generous amount of warm apricot glaze. Let cool completely on rack.