Preheat your oven to 325°F (163°C) and line a sheet pan with parchment paper.

Sauté the onions, fresh thyme, kosher salt, and black pepper in olive oil over medium-low heat for 8–10 minutes until the onions are soft.

Stir in the Worcestershire sauce, chicken stock, and tomato paste. Allow to cool slightly.

In a large bowl, gently combine the ground chuck, cooled onion mixture, bread crumbs, and beaten eggs using a fork.

Shape the mixture into a loaf on the prepared sheet pan and spread the ketchup evenly over the top.

Bake for 1 hour to 1 hour and 15 minutes until the internal temperature reaches 160°F (71°C).

Allow the meatloaf to rest for 10 minutes before slicing.