Preheat your oven to 350 degrees F. While the oven is heating, prepare your 6 mini tart pans with removable bottoms. This will ensure easy removal after baking.
In a mixing bowl, combine the graham cracker crumbs, salted butter, granulated sugar, ground cinnamon, and finely chopped pecans. Mix everything together until the crumbs are fully moistened and have a sandy texture.
Evenly distribute the crust mixture among the 6 prepared tart pans, pressing it firmly into the bottom and up the sides. This will create a sturdy shell for your tarts.
Place the tart pans on a cookie sheet and bake the crusts for about 10 minutes, or until they are slightly browned and fragrant. Keep an eye on them to avoid burning, as oven temperatures can vary.
While the crusts are baking, prepare the filling. In a large mixing bowl, whisk together the light corn syrup and brown sugar until smooth and combined.
Next, add the melted butter to the sugar mixture, whisking to combine. Then, crack in the eggs one at a time, beating well after each addition until the mixture becomes smooth and slightly foamy.
Now, stir in the instant espresso powder, vanilla extract, ground cinnamon, and kosher salt. Mix until well incorporated, making sure there are no lumps.
To ensure a smooth filling, gently rap the bowl against the counter a few times to eliminate any air bubbles that may have formed while mixing.
Carefully fold in the pecan halves and bittersweet chocolate to the filling mixture, ensuring they are evenly distributed throughout.
Now, pour the filling into the pre-baked crusts, filling each tart to just below the rim. Bake for an additional 15 to 20 minutes, or until the filling is set but still slightly jiggly in the center. You can test for doneness by gently shaking the pan.
Once baked, remove the tarts from the oven and allow them to cool for at least 20 minutes before attempting to remove them from the pans. This cooling time allows the filling to firm up further.
