Mix yogurt with 2 tablespoons maple syrup.
Wash and peel the pears, remove the core and cut the flesh into thin wedges.
Toast the bread or fry it in a grill pan with olive oil.
Spread yogurt on each slice of bread, place the pear wedges on top and sprinkle with the hazelnuts.
Pluck the lemon balm and garnish the crostini with it. Drizzle the remaining maple syrup over the top.