Finely dice your onions.

In a frying pan over low-to-medium heat, melt a generous amount of butter.

Add the onions and sauté them until they are soft and translucent (about 3/4 cooked).

Transfer the onions and melted butter into a bowl and let them cool to room temperature.

Once cooled, use an immersion blender to process the onions and butter into a smooth, creamy paste.

Use ground beef with an 80/20 lean-to-fat ratio (80% lean beef, 20% fat).

Add the prepared onion-butter paste to the meat.

Season with salt, black pepper, and a small amount of fine breadcrumbs.

Pro Tip: Gently fold and mix the ingredients by hand until just combined. Do not over-knead or "work" the meat like dough, as this will make the burgers tough. Keeping the mix light ensures a tender, "crumbly" texture when eaten.

Using a kitchen scale, portion the meat into balls weighing approximately 110g to 120g each.

Place a sheet of plastic wrap (nylon) on your workspace.

Place a meatball on the wrap, cover it with another layer of plastic wrap, and gently flatten it with your hand into a rough circle.

Take a flat-bottomed plate or dish and press down firmly and evenly over the meat to create a perfectly uniform, round patty.

Repeat for the remaining portions.

Place the shaped patties in the freezer for approximately 2 hours. This helps the butter solidify and the flavors meld, ensuring the patty holds its shape perfectly when it hits the grill or pan.

Once chilled, the patties are ready to be grilled or pan-fried to your preferred level of doneness.