Preheat oven to 350℉ and grease an 8-inch tart pan, preferably one with a removable bottom.
Blend the crust ingredients together in a food processor until combined. Press dough into your greased 8-inch tart pan. Make sure to go up on the sides of the pan with the dough. Use a fork and poke the crust in several spots on the bottom.
Bake at 350℉ for 20 minutes.
Let the crust cool. The bottom will fall when it cools, but that is fine.
To make the filling, place a medium saucepan over medium-high heat and add the butter. Let it heat until just starting to brown. Reduce heat to medium.
Add the cinnamon and allulose. Stir until sweetener is dissolved and color is uniform.
Pour in heavy cream and stir continuously for a couple of minutes. It will start to thicken and darken in color and look like caramel. Remove from heat and add in pecans.
Add filling to the cooled tart shell and refrigerate for at least one hour.