Preheat your oven to 375°F (190°C). Gather your ingredients.

In a mixing bowl, combine ground beef, diced onion, quick oats, whole milk, eggs, Worcestershire sauce, sea salt, garlic powder, and half of the ketchup. Mix gently.

Let the mixture rest at room temperature for about 10 minutes.

Transfer the mixture into a lined loaf pan or onto a baking sheet and shape into a loaf.

Spread the remaining ketchup evenly over the top.

Bake for 45 minutes, until the internal temperature reaches 165°F (74°C).

Remove from the oven and let it rest for about 10 minutes before slicing.