The greens in this side dish also create a nice contrast to the creamy, velvety potatoes.
Divide between 2 large baking sheets and spread in an even layer.
Meanwhile, heat the remaining 2 tablespoons oil in a large saucepan over medium heat.

Add onion; cook, stirring frequently, until very soft and golden brown, 5 to 8 minutes.
Add garlic; cook, stirring, until fragrant, about 1 minute more.
Add, flour, salt and pepper; cook, stirring for 1 minute more.
Add milk; cook, stirring and scraping up any brown bits at the bottom of the pan.
Squeeze spinach to remove any excess moisture; stir into the sauce.
When the potatoes are done, remove them from the oven.
Transfer half the potatoes to a 2-quart broiler-safe baking dish.
Spread half the sauce over the potatoes and top with 1/2 cup cheese.
Add the remaining potatoes and top with the remaining sauce and cheese.
Let stand 10 minutes before serving.
Tips
To make ahead: Roast potatoes (Step 2) up to 30 minutes ahead.
- Daily Values (DVs) are the recommended amounts of nutrients to consume each day.
(-) Information is not currently available for this nutrient.