Preheat oven to 350° F. Prepare syrup by simmering sugar, maple syrup, water and cinnamon sticks for 10 minutes. Remove from heat and stir in hazelnut liqueur. Add hazelnuts and let soak for 3 minutes (just to absorb a little sweetness). Strain off liquid and pour it into an 8-inch square baking dish. Roughly chop soaked hazelnuts and spread on a parchment lined baking sheet. Toast in the oven for 6 to 8 minutes, until golden brown.
While hazelnuts are toasting prepare pears. Peel pears, cut in half and core. Pour syrup over pears. Roast pears for 20 minutes, until they are soft when pierced with a tester.
To serve, place pear in a bowl, drizzle syrup over and sprinkle generously with hazelnuts.