Heat a cast iron skillet over the stove — first at high heat to get the pan very hot, but then reduce the flame all the way to low. We like the slow-cooked grilled cheese sandwiches.
Using a pastry brush, lightly coat each side of each slice of bread. Spread a healthy layer of goat cheese on the bottom slice, and then arrange your cucumber slices on top of the goat cheese. Carefully place the first half of your sandwich on the skillet, and sprinkle with salt and pepper, if you like.
Then, spread a thin layer of goat cheese on the next slice. Place this slice on top of the first one, and let it sit on the stove for about five minutes — make sure your heat is LOW. Use a spatula to lift the bottom slice — if it’s nice and golden, go ahead and flip your sandwich. Let that side sit for four to five minutes. When the second side is just as golden, go ahead and remove the sandwich from the pan.