Preheat your oven to 350°F (175°C). This step is crucial to ensure even cooking.
Line a baking sheet with parchment paper. This helps prevent the bark from sticking and makes for easier clean-up.
In a mixing bowl, combine 1 cup of melted unsalted butter, 1 cup of packed light brown sugar, 2 cups of chopped pecans, 1 teaspoon of vanilla extract, and 1/4 teaspoon of salt. Stir until everything is well combined.
Spread the mixture evenly onto your prepared baking sheet. Aim for an even layer to ensure uniform baking.
Bake in the preheated oven for 10-12 minutes, or until the mixture is golden brown. Keep a close eye on it as baking times can vary.
Remove from the oven and allow it to cool completely on the baking sheet. Once cooled, break it into pieces, or cut it into squares, depending on your preference.