Preheat the oven to 350°F. Line a 9x13-inch baking pan with non-stick foil, pressing it carefully into the corners and up the sides.

Place the graham crackers and chopped pecans in a food processor and pulse until crumbly. Add the melted butter and vanilla bean paste and pulse until combined. Pour into the prepared pan and press firmly to form an even crust.

Place the softened cream cheese, granulated sugar, and vanilla bean paste in a large bowl and beat with an electric mixer until smooth. Add the eggs one at a time, beating after each addition. Add the sour cream and mix just until combined.

Pour the filling over the crust and smooth the top. Bake for 50 minutes. When the baking time is up, turn off the oven and open the door. Leave the cheesecake to rest in the open oven for 15 minutes. This gradual cooling prevents the top from cracking.

Remove from the oven and let cool completely at room temperature before adding the caramel topping. The cheesecake must be fully cooled and set before the caramel goes on, or the heat from the sauce will soften the filling and prevent clean slicing later.

Set a small saucepan over medium heat and add the brown sugar and butter. Stir until the butter is melted and the sugar is dissolved. Add the condensed milk, corn syrup, and vanilla bean paste. Bring to a boil, stirring continuously, until a candy thermometer reads 220°F. Remove from heat and set aside for 5 minutes. Allowing the caramel to cool slightly before pouring prevents it from melting into the cheesecake filling and keeps it as a distinct, defined layer on top.

Pour the caramel evenly over the cooled cheesecake. Refrigerate overnight. The overnight rest is essential. It allows the caramel to fully set, the flavors to develop, and the bars to firm up enough to slice cleanly. Bars sliced before fully setting will not hold their shape.

Just before serving, sprinkle each bar with flaky sea salt. Serve chilled.