Preheat the oven to 350°F (175°C) and position a rack in the middle.
In a food processor, pulse the pecan shortbread cookies and chopped pecans until they form fine crumbs.
Add the melted butter to the crumbs and pulse until evenly moistened.
Press the crumb mixture into the bottom and up the sides of a 9-inch pie pan using the bottom of a measuring cup; refrigerate until firm, about 20 minutes.
Bake the chilled crust in the preheated oven until lightly browned and fragrant, about 15 minutes; cool to room temperature.
Meanwhile, heat a medium skillet over medium-high and combine the drained crushed pineapple, 1/4 cup sugar, and a pinch of salt; cook, stirring occasionally, until the pineapple is lightly browned and the liquid has evaporated, about 15 minutes.
Transfer the cooked pineapple to a food processor and process until smooth, about 1 minute; set aside.
In a medium bowl, whisk together the egg yolks, the remaining 1/4 cup sugar, and 1/4 teaspoon salt; set aside.
In a medium saucepan, combine the pineapple-flavored gelatin with 1/2 cup of the thawed pineapple juice concentrate; let sit until the gelatin softens, about 5 minutes.
Warm the gelatin mixture over medium heat, stirring, until the gelatin dissolves and the liquid is very hot but not boiling, about 2 minutes.
Whisking vigorously, slowly add the hot gelatin mixture to the egg yolk mixture to temper the yolks.
Return the combined yolk mixture to the saucepan and cook over medium heat, stirring constantly, until slightly thickened, about 2 minutes; remove from heat.
Stir in the remaining 1/2 cup pineapple juice concentrate and the processed pineapple until smooth; transfer to a bowl and refrigerate until set, about 1½ hours.
Whip the chilled heavy cream with the remaining 1 tablespoon sugar in a stand mixer or with a hand mixer on medium-high until stiff peaks form, about 3 minutes.
Fold 2 cups of the whipped cream into the chilled pineapple mixture in two additions until well combined.
Scrape the filling into the cooled crust and smooth the top, then spread the remaining whipped cream over the pie.
Refrigerate the pie until fully set, at least 4 hours or overnight.