Preheat the oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper (or foil), leaving overhang on the sides for easy lifting.
Make the crust/crumble: In a large bowl, whisk together the flour, brown sugar, and salt. Cut in the cold butter with a pastry blender or fork until the mixture looks like coarse crumbs with some pea-size pieces.
Press about two-thirds of the crumb mixture firmly into the bottom of the prepared pan to form an even crust. Reserve the remaining crumbs for the topping.
Bake the crust for 18–20 minutes, until the edges are lightly golden. Let the crust cool in the pan for about 10 minutes.
Meanwhile, make the caramel pecan filling: In a medium saucepan over medium heat, combine the butter, brown sugar, honey, and salt. Stir until melted and smooth, then bring to a gentle boil.
Let the mixture bubble for 3–4 minutes (no stirring during this time) to thicken slightly. Remove from heat and carefully stir in the heavy cream and vanilla, then fold in the chopped pecans.
Pour the hot caramel-pecan mixture evenly over the warm crust. Sprinkle the reserved crumb mixture over the top.
Return the pan to the oven and bake for 18–20 minutes, until the caramel is bubbling and the topping is lightly golden.
Cool completely in the pan until set (about 2 hours; chilling in the fridge helps for clean cuts). Lift out using the parchment overhang and slice into bars.