Preheat oven to 375°F (190°C).

Line a 9-inch pie pan with pie shell.

Cook bacon in microwave until crispy (about 7 minutes).

Crumble the cooked bacon.

In a mixing bowl, beat eggs with a mixer until light and frothy.

Add onion salt and shredded Swiss cheese to the eggs.

Stir in the crumbled bacon and chopped green onion.

Pour in the whole milk and blend well with the mixer until fully combined.

Pour the mixture into the prepared pie shell.

Bake in the preheated oven for 30 to 35 minutes, or until the custard is set and the crust is golden brown.

Let the quiche sit for about 5 to 10 minutes before cutting and serving.