Spread the pecans on a baking sheet and toast them in the oven for about 10 minutes or until fragrant.
In a saucepan over medium heat, melt the butter.
Stir in the brown sugar, corn syrup, and sweetened condensed milk.
Bring the mixture to a boil, stirring constantly. Let it boil for 5 minutes without stirring.
Remove from heat and stir in the vanilla.
Mix the toasted pecans into the caramel mixture.
Drop spoonfuls of the mixture onto waxed paper and let them cool until set.
Enjoy your delicious clusters!
Notes
You can drizzle melted chocolate over the clusters for an extra chocolatey treat. Feel free to mix in other ingredients like dried fruit or coconut for added flavor!