Scalloped Potatoes

Ingredients:
       3 tbl. butter
       1      onion (small)
       4      garlic cloves (minced)
     1/4 C    flour
       1 C    chicken or vegetable stock
       2 C    milk
   1 1/2 tsp. salt
       4 lb   Yukon Golds (1/8" sliced rounds)
       2 C    sharp cheddar (grated)
     1/2 C    Parmesan cheese (grated)

Directions:
   1) Pre-heat oven to 400 F.  Grease 9x13 baing dish.
   2) Melt butter in 4qt pot.  Add onion and sauge for 4-5 minutes or until
      translucent.  Add garlic and saute until fragrant (1-2 minutes).
   3) Stir in flour until onions and garlic are coated and cook for 1-2 minutes.
   4) Slowly add milk and stock while whisking mixture.  Then whisk in salt,
      pepper, and 1 tsp. of thyme. Cook for 1-2 minutes or until sauce just
      starts to simmer and thicken. Remove from heat and set aside.
   5) Spread half the sliced potatoes in an even layer on the bottom of the pan.
      Spread half the cream sauce evenly over the potatoes. Sprinkle 1 c of the
      cheddar and all of the parmesan cheese across the top.  Layer remaining
      potatoes, cream sauce, and cheddar cheese.
   6) Cover pan with foil and bake for 30 minutes.  Remove foil and bake 
      uncovered for 25-30 minutes longer or until the potatoes are cooked.
   7) Remove from oven and garnish with remaining thyme and extra parmessan
      cheese (if desired).


Notes:
   The recipe can be made without flour.  Using a separate pot, simmer a small
   potato in the milk until it is very soft.  Mash the potato into the milk and
   whisk until smooth.  Skip step 3 and add the potato milk in step 4.


Source:
   https://www.gimmesomeoven.com/scalloped-potatoes-recipe/
