Throw onions, thyme, salt and pepper and cook over medium to low heat, stirring occasionally. About 8 to 10 minutes,.
Turn off the heat, add the Worcestershire sauce, chicken stock, and tomato paste. Permit to cool slightly.
Combine chicken stock, ground chuck, onion mixture, bread crumbs, and eggs in a bowl and and mix lightly with a fork. Do NOT mash or the meat loaf will be dense.
Shape the mixture into a rectangular loaf on a sheet pan covered with parchment paper.
Spread the catsup evenly on top. Bake for 1 to 1 1/4 hours, until the internal temperature is 160 degrees F and the meat loaf is cooked through.