French Braised Short Ribs in a Red Wine Sauce

Ingredients
10 bone-in 2-inch-thick short ribs (3 lbs.)
1/4 cup vegetable oil
3 carrots, bias cut
1 stalk celery, bias cut
2 leeks, roughly chop
3 garlic cloves, smashed
2 tablespoons tomato paste
1 cup red wine
1/2 cup beef broth
3 sprigs fresh thyme
1 sprigs fresh rosemary
1 tablespoon butter, softened
2 cups + 2 tablespoons all purpose flour
Kosher salt and freshly cracked black pepper, to taste
Optional: chopped chives to garnish
Preparation