Step 1

Preheat the oven to 350°F and grease a 9x13 dish.

Step 2

Cook onion and garlic in the butter in a saucepan until tender.

Step 3

Stir in flour, salt, and pepper.

Step 4

Add milk and stir over medium heat until thickened and just starting to simmer.

Step 5

Remove from heat, and mix in cheese until melted. Set aside.

Step 6

Place half the potatoes in the dish.

Step 7

Top with half the cheese sauce.

Step 8

Repeat layers.

Step 9

Cover tightly with foil and bake for 45 minutes.

Step 10

Uncover and bake an additional 45 minutes or until the potatoes are tender.

Step 11

Let stand uncovered for 10 minutes before serving.