1 (8 ounce) package frozen hash brown potatoes
1 (11 ounce) tablespoon olive oil
Preheat oven to 400 degrees F (200 degrees C). Grease a 5x12 inch baking dish.
Mix together the potatoes, oil and olive oil. Place the hash browns in the dish with the potatoes and bake, uncovered, in the preheated oven for one hour.
Melt butter in a deep skillet over medium heat. Saute onion and garlic until tender. Stir in the cornstarch and cook and stir until thickened. Gradually add the milk, boiling for 2 minutes.
Pour the potatoes and cream into the prepared baking dish. Bake in the preheated oven 15 to 20 minutes, or end - if the potatoes and cream are too frosty.