Sprinkle meat lightly with salt and pepper, coat with flour
Brown well in heated oil in a large frying pan
Reduce heat
Add onion and celery, cook until limp
Transfer roast to a deep 4-quart casserole
To vegetables in pan add garlic, thyme, mustard and broth
Bring to boiling, stirring in pan drippings
Pour mixture over meat
Cover and bake at 325 degrees until meat is almost tender, about 2 1/2 hours
Add carrots and wine
Cover, continue baking 30 to 35 minutes
Remove meat and carrots to a platter, keep warm
Strain cooking liquid; skim fat, reserving 2 tablespoons
To this fat in a saucepan add cornstarch, stirring; cook until bubbly
Remove from heat
Gradually mix in cooking liquid (about 3 cups)
Return to heat
Cook, stirring constantly, until thickened
Taste; add salt, if needed
Slice meat, serve with sauce spooned over
Sprinkle with parsley