Burger:

1. Preheat your grill or skillet to medium-high heat.
2. Weigh your portion of ground beef and shape it into a 3 oz ball.
3. Using a heavy spatula, smash the patty into the pan.
4. Season patty with onion, salt, and pepper.
5. When the patty develops a crust, use the back side of the spatula to run under the patty and pull it apart from the pan.
6. Cook for 3-4 minutes per side or until it reaches your desired level of doneness. During the last minute of cooking, add a slice of cheese to the patty and let it melt.

Burger Sauce:

1. In a small bowl combine all ingredients. Use a whisk to mix thoroughly.

Assembly:

1. Toast buns.
2. Spread the sauce on the bottom half of each bun.
3. Add a patty with melted cheese on top.
4. Finish with the top half of the bun.