Preheat oven to 325°F. Line a square baking pan with parchment paper, leaving overhang on all sides.
Add butter, brown sugar, honey, and salt to a small saucepan.
Heat over medium-high heat until the mixture reaches a boil.
Reduce heat to low and simmer for 2 minutes, stirring occasionally.
Place granola in a large mixing bowl.
Pour the hot syrup over the granola and stir until evenly coated.
Transfer the mixture to the prepared pan.
Press firmly into an even layer using a spatula or the bottom of a measuring cup.
Bake for 20 minutes or until lightly golden and set.
Cool completely in the pan.
Use the parchment sling to lift the granola from the pan.
Transfer to a cutting board and cut into 12 bars.