Scrub the russet potatoes thoroughly under cold running water to remove any dirt, then pat them dry. Using a fork, pierce each potato multiple times all over—this prevents them from bursting during cooking and allows heat to penetrate more evenly. This prep work takes just a few minutes but makes a significant difference in cooking time and texture.

Preheat your grill to 300°F (or use a 300°F oven if you prefer). Place the pierced potatoes directly on the grill grates and cook for approximately 90 minutes, or until a meat thermometer inserted into the center reads 205-210°F. This low-and-slow method creates incredibly creamy potatoes by allowing the starch to fully gelatinize. I find that grilling adds a subtle smoky depth that you won't get from boiling.

Remove the potatoes from the grill and let them cool for 5-10 minutes until they're comfortable to handle. Once cooled slightly, cut each potato in half lengthwise and use a spoon to scoop out the soft interior flesh, leaving the skin behind. Discard the skins and place all the scooped potato flesh into a medium bowl—you should have roughly 4 cups of cooked potato.

Mash the hot cooked potatoes vigorously with a potato masher until mostly smooth, though a few small lumps are fine and add texture. While the potatoes are still warm, add the butter and stir until fully melted and incorporated. The residual heat will help the butter distribute evenly throughout the potatoes, creating a silky base.

Pour in the half and half and chicken stock gradually while stirring constantly, mixing until you reach your desired consistency—start with three-quarters of the liquid and add more as needed for a smooth, creamy texture. Add the salt, seasoned salt, black pepper, and garlic powder, stirring well to combine. I prefer to taste and adjust the seasonings at this point rather than relying solely on measurements, as different brands of broth vary in saltiness. Heat gently over low heat (or on the stovetop) for 2-3 minutes, stirring occasionally, until the mixture is smooth, creamy, and warmed through.