Finely chop the onion and soak in water for 10 minutes. Drain well. Slice the tomato into 1cm thick pieces.

For the meat sauce: Roughly chop the onion, celery, and carrot.

Heat butter in a pan, add ground meat, and cook over medium heat until browned. Add the chopped vegetables and sauté briefly. Stir in flour and mix well.

Add the seasoning ingredients (red wine, tomato puree, etc.) and bring to a boil. Lower the heat, cover, and simmer for 30 minutes.

Blend the sauce using a blender until smooth.

For the patty: Finely chop the onion and microwave for 1 minute at 600W. Let it cool.

Combine patty ingredients in a bowl and mix until sticky. Divide into three portions and shape into flat circles.

Heat oil in a pan and cook the patties over medium heat until browned. Flip, cover, and cook on low heat for 5 minutes.