How to Make It
Preheat a panini press or a grill pan. Spread the bread slices with the goat cheese. Top half of the bread with the apple slices and horseradish. Close the sandwiches and butter the outsides.
Press the sandwiches until the bread is toasted and the cheese is warm, about 5 minutes. Alternatively, set the sandwiches on the grill pan, cover and grill over moderate heat, turning once, about 5 minutes. Cut the sandwiches in half, transfer to plates and serve right away.