Preheat oven to 350° F. Line a deep 9-inch cake pan or round baking dish with greased foil or parchment paper.
In a medium saucepan set over medium low heat, melt the butter and chocolate together until melted and smooth, stirring frequently. Remove from heat and stir in the sugar. Add the eggs one at a time, mixing after each, followed by the vanilla extract. In a separate bowl, combine the flour, cinnamon and salt. Add to the chocolate mixture and mix just until no streaks of flour remain.
Spread batter into the prepared pan and bake for 20 minutes.
While the brownies are baking, prepare the pecan pie filling. Whisk together the honey or light corn syrup, brown sugar, eggs and vanilla. Slowly add the melted butter and mix until combined. Add the pecans and stir until they've all been coated in the filling.
After 20 minutes, remove the brownies from the oven and spoon the pecan pie filling on top into an even layer (do not pour or dump mixture on top).
Bake for an additional 30-35 minutes until center jiggles slightly when gently shaken. Cool completely to room temperature, for at least 2 hours, to completely set the brownies. If desired, chill in the fridge for a shorter cooling time.
Slice with a sharp knife and serve with ice cream, or as desired.