In one quart pot, melt 4 Tablespoons butter on medium heat, being careful not to burn it.
Add 1 Tablespoon flour, 1 teaspoon sea salt, and stir until well blended.
Add 4 more Tablespoons flour, 1 Tablespoon at a time, stirring each until well-blended and the mixture pulls away from the sides of the pot.
Remove from heat. Add 1 cup milk (1/4 cup at a time) stirring until smooth, without clumps.
Return to heat and gradually add 3 more cups milk, while stirring. As the sauce thickens, stir to keep it from sticking to the pot and/or clumping. It is ready when it is the consistency of creamy gravy.
Add pinch of black pepper. Remove from heat and set aside. It will thicken a bit more while sitting.