Preheat oven to 350°F (180°C). Spray a 9-inch springform pan with baking spray with flour.
In a medium bowl, stir together graham cracker crumbs, finely chopped pecans, and ¼ cup (50 grams) sugar. Add melted butter; stir until well combined. Press mixture into bottom of prepared pan.
Bake until lightly browned and fragrant, 10 to 12 minutes. Let cool on a wire rack for 30 minutes. Reduce oven temperature to 325°F (170°C), and position oven rack in bottom third of oven.
Wrap a large piece of heavy-duty foil around bottom and up sides of springform pan; place springform pan in a large oven bag, tucking ends so bag is flush with top edge of pan. (If you do not use an oven bag, wrap pan in a double layer of foil.)
In a medium bowl, whisk together flour and remaining 1¼ cups (250 grams) sugar.
In the bowl of a stand mixer fitted with the paddle attachment, beat cream cheese at medium speed until smooth and creamy, about 1 minute, stopping to scrape sides of bowl. Add flour mixture and vanilla; beat at medium-low speed until well combined, about 1 minute, stopping to scrape sides of bowl. With mixer on low speed, add eggs, one at a time, beating just until combined after each addition. Add sour cream; beat until well combined, about 30 seconds, stopping to scrape sides of bowl.
Transfer half of batter (about 3¼ cups or 771 grams) to a medium bowl, and stir in ¾ cup (212 grams) Caramel Sauce. Alternately pour plain and caramel batters onto prepared crust in pan. Swirl batters using a knife. Carefully place springform pan in a large roasting pan. Place roasting pan in oven, and add hot water to roasting pan to come 1 inch up sides of springform pan. (Make sure roasting bag extends up higher than water.)
Bake until edges are set but center jiggles slightly when pan is gently shaken, 1½ hours to 1 hour and 45 minutes. Carefully remove springform pan from water, and let cheesecake cool completely in pan on a wire rack, 1½ to 2 hours. (Once pan is cool enough to handle, carefully remove bag and foil from sides.) Refrigerate in pan on a wire rack overnight, loosely covering with foil only when completely cool to prevent condensation from forming on cheesecake.
Carefully remove cold cheesecake from pan, and transfer to a serving plate. In a medium bowl, stir together whole pecans and remaining Caramel Sauce. Gently spoon on top of cheesecake. Serve immediately.