Preheat your oven to 350°F (175°C) and arrange the Lil' Smokies in an even layer in a 9x13-inch baking dish.
In a small bowl, whisk together the melted butter, dry ranch dressing mix, brown sugar, garlic powder, and pepperoncini juice until smooth.
Pour the butter and ranch sauce evenly over the sausages in the baking dish.
Scatter the sliced pepperoncini peppers over the top of the sausages.
Bake for 20 to 25 minutes, stirring once halfway through, until the sauce is bubbly and forms a glossy glaze.
Serve warm with toothpicks for easy grabbing.