Peel the pears, cut them lengthways and core them. Brush the pears with lemon juice to prevent them from turning brown. Place the pears in a coated roaster with the convex side up.
Put the cinnamon, sugar and semi-fat margarine in a small saucepan and heat it over a low heat while stirring until the sugar melts. Then drizzle the mixture over the pears.
Bake the pears for 20-25 minutes until they are soft and golden brown. Douse them with the sugar solution from time to time.
Warm the vanilla sauce and distribute it on 4 dessert plates. Put 2 pear halves in each plate and garnish with strips (zest) from a lemon zest to garnish and serve.