Prepare the pear wood ice cream first as it will take the longest and needs to be frozen before you can use it. Bring the milk to a boil. Roast the wood in the oven at 160°C and infuse in the milk for 10 minutes. Then sieve out the wood and mix the previously boiled sugar, sour cream, jelly sugar and water with the milk/wood mix. Pour the mixture into the ice cream maker and freeze. If you don't have an ice cream maker, you can put the mixture in the freezer and stir with a beater every 15 minutes. Leave the mixture in the freezer until the consistency is similar to that of ice cream. For the Comice pear cakes, the pears are either cooked in water for three hours at 75°C using the sous-vide method, or for six hours at 80°C and then pureed. Next, mix butter, flour, baking powder, Birnel, eggs and puree, fill bake-proof glasses with 80 g each and bake in the oven at 180°C for 12 minutes. The pear vinegar ice jelly must also be cooked for three hours at 75°C using the sous-vide method or for six hours at 80°C. To do this, mix the pears and the vinegar together. In the meantime, bring the pectin to a boil, allow to cool to 40°C and mix with the soaked gelatine. Pour into a suitable container. For the ganache, cook the Thirriot Pear with pear brandy and water at 75°C sous-vide or cook until soft in a pot for six hours at 80°C. Puree the entire mixture and allow to cool.