Wash the lettuce, dry and tear into bite-sized pieces.
Wash and quarter the pear, remove the core and cut into slices.
Roughly chop the walnuts.
Mix the mustard with the vinegar, salt and pepper in a bowl. Add the oil slowly, whisking constantly, to form a vinaigrette. If desired, sweeten with some honey or apple juice.
Cut the goat's cheese into 4 even slices.
Place the cheese on the bread slices, season with black pepper and place on a baking tray. Cook in the preheated oven at 200°C (180°C fan, gas 6). Toss together the lettuce, pear slices and walnuts then drizzle over the dressing. Serve with the warm cheese toasts.