Season the chuck roast generously with salt & pepper; massage into meat.

Dredge through flour shaking off any excess.

Heat 6 quart low pressure cooker over medium heat, add oil, then heat until shimmering. Sear roast on all sides until golden brown (about 15 minutes) Remove from pan & set aside.

Add onions, carrots, celery & tomato paste to pan, stir well to coat. Cook about 2 to 3 minutes.

Add bay leaves, garlic & thyme. Stir cooking about 1 minute.

Add roast & resting liquid to pan, then add chicken stock to come about halfway up roast. Bring all to a simmer. Cover making sure it is well sealed. Cook on a medium, low flame, an active simmer for about 1 hour.

Carefully remove lid, and remove pot from heat. Carefully remove roast from pan and set aside, pour contents of pan through a strainer into a large bowl.

Press liquid from vegetables with a spatula - discard vegetables.

To Finish:

In a small bowl whisk 2 tablespoons of flour with 3 to 4 tablespoons of broth from the pan to form a liquid paste.

Place pot back on medium heat, add 2 tablespoons of cooking oil to heat.

Saute onions & mushrooms about 2 minutes.

Add to pot along with tomato paste, carrots, potatoes and flour mixture.

Stir well and season with salt & pepper.

Pour strained cooking liquid back into pan, stir well. Bring to boil then reduce to a simmer.

Add roast back to pan & cover. Seal lid well and simmer bout 15 minutes.

Once done, remove roast and rest for about 10 minutes. Slice meat against the grain & place on platter.

Arrange vegetables around it and lightly dress with sauce. Sprinkle over with fresh parsley.

Serve remaining sauce on the side.