Make rosemary butter: In a small ramekin, mix together softened butter, minced fresh rosemary, garlic powder, and a pinch of sea salt until smooth and spreadable.

Prep bread & spreads: Lay the 4 sourdough bread slices on a clean cutting board. Spread one side of two slices with Dijon mustard, and spread the other two slices with generous spoonfuls of whole-berry cranberry sauce.

Layer ingredients: On the bottom cranberry-spread slices, layer half of the sliced brie cheese. Top evenly with thick carved roasted turkey breast, a handful of fresh baby arugula, and cracked black pepper. Cover turkey with remaining slices of brie cheese (double brie locks in moisture!) and top with the second bread slice.

Butter outside crusts: Brush the outside of both top and bottom bread slices generously with the fragrant rosemary garlic butter.

Grill to molten perfection: Heat a cast iron grill pan, panini press, or heavy skillet over medium-low heat. Place paninis in the skillet. If using a skillet, press down firmly with a heavy skillet or foil-wrapped brick. Cook 4 to 5 minutes per side until the sourdough is deeply golden, crisp with grill marks, and the brie cheese is completely melted and oozing out the edges.

Slice & serve: Let rest on cutting board for 1 minute so the cheese settles slightly. Slice diagonally in half with a serrated knife and serve immediately while hot and gooey.