"OMG! I took one bite, and I swear I heard angels sing. This is next-level cheesy goodness!" What do...

"OMG! I took one bite, and I swear I heard angels sing. This is next-level cheesy goodness!"
What do you need to make Not So Impossible Cheeseburger Pie

1 ½ cups milk

1 ½ cups chopped onion

¾ cup baking mix, such as Bisquick

½ tsp salt

½ tsp black pepper

2 tomatoes, sliced

1 cup Cheddar Cheese, shredded

½ Italian Seasoning
3 eggs

1 pound ground beef