Pat dry chicken breasts. Soak chicken breasts in buttermilk for about 30 minutes in fridge.
Fry the chicken on both sides until golden.
Drain the fried chicken on paper towels immediately after removing from the oil and then allow to cool.
In saucepan, melt 2 Tablespoons of butter over medium-high heat. Add mushrooms and cook until golden and excess mushroom liquid evaporates, about 10 minutes.
Add garlic and remaining butter (4 tablespoons). Cook for about 1 minute.
When gravy starts to boil, reduce heat to low. Stirring often, simmer until thickened, about 15-20 minutes depending on your preferred thickness. Check for seasoning and salt again if needed.
Note 1: To quickly make a homemade buttermilk, combine 1 cup of milk with 1 tablespoon of lemon juice.
Stir to combine and allow to sit at room temperature for 5-10 minutes. Use as directed for buttermilk in the recipe.