This sourdough panini sandwich layers smoked Gouda, deli ham, Granny Smith apple, and fresh lettuce between two slices of sourdough bread, pressed until the cheese melts and the crust turns golden and crisp.
Prep the fillings – Slice the Granny Smith apple and vine-picked tomatoes to about ⅛ inch thick and set aside.
Spread the bread – Lay all four slices of sourdough flat. Spread mayonnaise and mustard on the inner face of each slice going all the way to the edges.
Layer the fillings – on two slices of bread, layer one slice of smoked Gouda, two slices of deli ham, a few apple slices, and a light sprinkle of coarse salt and cracked peppercorn. Add tomato slices now if using. Add a second slice of smoked Gouda on top of the filling before the top slice of bread goes on.
Butter the outside – Spread a thin even layer of butter on the outer face of each slice of bread on both sandwiches.
Preheat the skillet – Heat a cast iron skillet over medium heat until fully preheated and the butter sizzles gently on contact.
Press and cook the first side – Place the sandwiches butter-side down in the skillet. Set a heavy pan on top and press firmly. Cook for 3 to 4 minutes until the underside is deep golden and the bread has a visible crust.
Flip and finish – Remove the weight, flip each sandwich carefully, replace the weight, and cook for another 3 to 4 minutes until the second side matches the first and the smoked Gouda is fully melted.
Rest, add lettuce, and slice – transfer to a cutting board and let rest for 1 minute. Open each sandwich and tuck one leaf of fresh butter lettuce inside, then close and slice each sandwich diagonally and serve immediately.
Video
Notes
Slice apple and tomato thin – About ⅛ inch on both so everything compresses evenly and the filling does not shift during pressing.Butter the bread not the pan – Buttering the outer faces of the bread directly produces a more even golden crust all the way to the edges than buttering the skillet.Use medium heat – Medium heat gives the smoked Gouda time to melt fully before the crust goes past golden. High heat produces a crispy exterior with unmelted cheese at the center.Rest before slicing – One minute off the heat lets the melted cheese set slightly so the filling stays in the layers when the sandwich is cut.