After roasting beef, transfer meat to a resting pan and reserve pan drippings.
Pour drippings into a heatproof measuring cup and let fat separate; skim off excess if desired.
In a saucepan over medium heat, add 1 tbsp reserved fat or butter and sauté minced shallot until translucent.
Add smashed garlic and cook about 30 seconds until fragrant.
Stir in tomato paste and cook briefly to deepen flavor.
Pour in red wine (if using) and deglaze the pan, scraping up browned bits.
Add beef stock and the reserved pan juices; stir to combine, then add bay leaf and thyme.
Bring to a gentle simmer for 6–8 minutes, tasting and adjusting seasoning with Worcestershire, salt, and pepper.
If a slightly thicker jus is desired, whisk in cornstarch slurry and simmer until glossy.
Remove bay leaf and thyme stem, strain through a fine-mesh sieve, and serve warm alongside sliced roast or for dipping sandwiches.