For the condensed soup, preferred is using 1 Family Size (26 oz) can, as an alternate you can also use 2 regular size cans (10.5 oz each) mixed with ¼ cup milk.
In a non stick pan on medium heat, cook the ground beef and onion, breaking up the beef with your spatula as it cooks. Season with salt and pepper as desired. Cook until there is no more pink visible, drain off any fat.
Preheat your oven to 190° C (375° F), grease a 9x13 baking pan with butter or cooking spray.
Add beef to the prepared baking pan and spread out in an even layer.
Sprinkle the peas over the beef in an even layer.
Spread the condensed soup over the peas in an even layer. If using 2 cans of regular size soup, empty both into a mixing bowl and mix with ¼ cup of milk in addition to the sour cream, then spread over the peas in an even layer.
Lay the tater tots in a single layer on top of the soup.
Bake uncovered for 35 minutes or until the tots are starting to brown and the casserole is bubbly.
Serve and enjoy.