So, I'm a little forgetful... and by a little - sometimes a lot. For the past three weeks I have neglected to alter our greenBEAN delivery box which results in a surplus of potatoes. Which isn't entirely bad, since they are organic and sustainably grown fingerlings - but none the less, we have a butt load of potatoes.
In a quest to de-potato our fridge, I came across this goodie on Smitten Kitchen's site - Simple Potato Gratin. With just a few adjustments - we ended up with slightly healthier (so we kid ourselves) Potato Gratin with Spinach and Mushroom!
3 tablespoons butter, cut into cubed pieces (plus more for the bottom of the gratin
dish and cooking the mushrooms and spinach)
1 1/2 pounds fingerling potatoes (or any other waxy potatoes - these work a bit better since the skins soften better in the oven)
1 cup milk
3 oz cheese parmesan, gruyere (yum), cheddar - whatever your liking! We used a
healthy mixture of white cheddar and parmesan
10 oz mushrooms (we used white button, but feel free to use any other variety), de-stemmed and sliced
1 cup (or generous handful) washed spinach salt/pepper
Pre-heat oven to 350 degrees fahrenheit. Melt cooking butter (I truthfully used 1 tablespoon Olive Oil) over medium heat in a sauce pan. Saute mushrooms until almost all the water is out of them. Depending on type this could take 10-20 minutes. Add spinach and stir until just wilted. Take off the heat for layering gratin. Wash and slice the potatoes very thin. Some use a knife, others a mandelin slicer - in my case - my food processor with the slicing blade. In a 9x12 inch gratin dish (or 9" round like mine...), smear the button with a bit of butter (to prevent sticking), and lay down in a thin layer, 1/3 of the potatoes. Sprinkle a third of the cheese, and a half of the spinach/mushroom mixture - salt and pepper to taste (this is important since a lot of the flavor comes from the salt and pepper...). Repeat one more time. On last layer - place last third of potatoes on top, with last third of cheese. Place the cubed butter on top and gently pour in milk. Bake for about an hour pushing the top gently down after 30 minutes.
Mine was filled to the top and started leaking so I had to put an old baking sheet beneath. This dish is great for leftovers, breakfast, lunch and dinner! Enjoy!