Season red deer filet and brown in a pan with a bit of olive oil. Finish cooking in the oven to 350°F (180°C) for about 10 minutes.
Caramelize sugar in a pan and brown French shallots. Add wine vinegar and 125 ml (1/2 cup) of blueberries. Then pour wild meat stock or veal stock and reduce for 10 minutes.
After baking, sieve the sauce and add the remaining blueberries into the sauce. Serve over the filet mignon.
Peel the celery root and pear then cut into pieces. Bake pieces in milk for about 20 minutes
Drain and transform the mixture in puree with a blender or a mixer. Season and serve.