Cut the bread horizontally into two halves. Remove almost all the pulp from the top half, leaving only 1 cm on the crust. The crumb is not needed in this recipe, use at your own discretion.
Grease both rugs of bread with vegetable oil from the inside (slices). Sprinkle half the base of the bread with goat cheese, top with basil leaves, tomato slices, ham and arugula leaves. Sprinkle with balsamic vinegar if desired. Cover the sandwich with a half-top (crust-lid).
Heat a large skillet over medium heat, brush with vegetable oil. Gently place the sandwich in the pan, cover with a second dry pan on top, press down slightly and cook for 2.5 minutes, then turn the sandwich over, press down again with the pan and fry for 2.5 minutes.
Transfer the sandwich to the plank, let it rest for about 4-5 minutes. Then cut the sandwich into 4 equal parts with a sharp knife.