Preheat your oven to 350°F (175°C). If you're using a frozen pie crust, allow it to thaw for about 10-15 minutes. If you're using a homemade pie crust, roll it out and fit it into a 9-inch pie plate. Trim the edges and flute them to create a decorative crust.
Cook the bacon on medium heat in a skillet until it's crispy. Remove the bacon from the pan and place it on a plate lined with a paper towel to absorb excess grease. Once cooled, crumble the bacon into small pieces.
If you're using fresh broccoli, wash and cut it into small florets. If you're using frozen broccoli, let it thaw and drain any excess water. Set aside.
In a medium bowl, whisk together the eggs, milk (or heavy cream), salt and black pepper until well combined. This will be your egg mixture, which will create a savory custard within the quiche.
Stir in the crumbled bacon, broccoli florets, green onions and cheddar cheese into the egg mixture.
Before adding the filling, you can "blind bake" the crust by placing a piece of parchment paper or aluminum foil over the crust, covering it with pie weights or beans. Bake for 10 minutes, then remove the weights and liner. This will help to avoid a soggy crust.
Pour the egg mixture into your prepared pie crust. Make sure the ingredients are evenly distributed within the crust.
Place the pie dish in your preheated oven and bake for 40-50 minutes, or until the center is set and the crust turns golden brown. You can check this by inserting a knife into the center to see if it comes out clean.
Remove the quiche from the oven and allow it to cool for 5-10 minutes before serving.