Preheat oven to 350°F. Line the inside bottom and sides of a 9-inch springform pan with parchment paper and spray with avocado oil spray. Wrap foil around the outside bottom as well and set aside.
Stir the almond flour, ground pecans, sweetener, and melted butter together until it resembles wet sand. Press the crumb mixture into the bottom of the prepared pan.
Bake for 10 minutes. Set aside to cool while you make the filling.
Make the filling:
Reduce the oven temperature to 300ºF.
In a large mixing bowl beat the cream cheese with a hand mixer on medium to medium-high speed until smooth and creamy, about 45 seconds.
Add the sweetener, sour cream, vanilla, and salt. Beat on medium speed until well combined.
Using a silicone spatula, gently stir in the eggs just until combined. Pour the batter into the prepared crust. Use an offset spatula to spread the batter evenly into the bottom.
Bake for 40 minutes. Once the cheesecake goes into the oven, begin working on the pecan pie topping.
Make the topping:
Place the salted butter in a medium saucepan. Heat over high heat while whisking until it froths up and brown flecks appear. Remove from heat.
Meanwhile, whisk the cream, sweetener, eggs, and extract together; once the butter has cooled a little, slowly add the egg mixture into the brown butter. Stir in the pecans.
Once the cheesecake has baked for 40 minutes, remove it from the oven.
Gently spoon the pecan topping over the cheesecake.
Return the pecan cheesecake to the oven and bake for another 30 minutes, until the top is golden brown and crisp. (If the edges of the pecan topping are over-browning during baking, cover with foil.)
Transfer to a wire rack and cool completely. Cover the cheesecake and refrigerate for at least 4 hours before serving.