For the pecan crust: Preheat the oven to 350 degrees F.
Place the pecans in the bowl of a food processor or blender. Pulse until finely ground. In a medium bowl, whisk pecans, flour, 3 packets of SPLENDA® Naturals Stevia Sweetener, and salt until combined. Melt butter then add to bowl and blend mixture well.
Transfer the mixture to a 8x8-inch or 9x13-inch baking dish; press flat. Transfer to the refrigerator to chill until firm, at least 20 minutes.
Bake until golden brown, about 15 minutes. Remove to a rack to cool.
For the cheesecake filling: Combine gelatin and 1/4 cup cold water in a bowl and stir to combine. Stir in corn starch. Bring the heavy cream to just a simmer in a small pot over medium-high heat. Add the hot cream to the gelatin mixture and stir to combine and dissolve. Set aside.
Beat the cream cheese, vanilla extract, and 26 packets of SPLENDA® Naturals Stevia Sweetener in the bowl with a mixer. Add the heavy cream-gelatin mixture and beat until smooth, scraping the sides of the bowl as needed. Pour filling into the cooled crust. Refrigerate until firm, at least 1 hour.
For the blueberry topping: Combine the blueberries and lemon juice in a medium saucepan. Bring to a simmer over medium heat and cook, stirring, about 4 minutes. In a small bowl, whisk together cold water, cornstarch, and gelatin. Allow to set for about 1 minute then pour mixture into the saucepan.
Carefully stir blueberries and cook for about 5 minutes. Remove from heat and stir in 2 packets of SPLENDA® Naturals Stevia Sweetener. Refrigerate blueberries for at least 30 minutes. Gently spread mixture over cheesecake filling.
Slice and serve.