Preheat the oven to 375 degrees. Set oven rack in the middle position. Spray a 9-inch springform pan with nonstick cooking spray.
To make the Crust: Combine the pecans, flour, brown sugar, butter, and salt in the bowl of a food processor fitted with the steel blade. Process until the pecans are finely ground. Transfer the crust mixture to the prepared pan. With your hands or the bottom of a dry measuring cup, pat mixture into an even layer. Place the pan on a baking sheet for easier handling.
To make the Filling: In a large bowl, whisk the eggs. Add the remaining filling ingredients and whisk until smooth. Pour the filling over the crust in the pan. Bake for about 30 minutes, or until the filling is set around the edges but still wobbly in the center.
To make the Streusel: As the torte is baking, in a medium bowl, combine the flour, oats, brown sugar, cinnamon, nutmeg, and salt. Mix until well combined. Add the butter pieces and, using your fingers, rub the butter into the other ingredients until the mixture is evenly moistened and clumpy. Stir in the pecans and refrigerate until ready to use.
Once the torte has baked for 30 minutes, remove it from the oven. Sprinkle the topping evenly over the partially baked filling (it will still be a little wobbly). Bake for 25 to 30 minutes more, until the filling is set and the topping is golden brown. Let the torte cool completely on a rack, about 4 hours. To serve, run a thin-bladed knife around the edge of the pan to loosen the torte from the sides, then remove the outer ring from the springform pan and transfer the torte to a platter. Serve and Enjoy.
Adapted from Once Upon a Chef