Use a medium-sized skillet, put it on low to medium flame. Cook Bacon in some Olive Oil till they are crispy.
Now, add Onions and cook till they are tender (golden in color) for approximately 10 minutes.
Remove the pan from the heat.
Add Flour, Salt, Pepper, Garlic Powder, and Parsley; stir the mixture properly till the blend is well.
Now gradually add milk to the mixture, continuously stirring, so no food lumps are made. Cook on the low flame will the sauce thickens.
Then add Spinach and cook well. Keep warm until ready to serve.