Sardine Pizza

• 1 large white onion
• 2 tablespoons unsalted butter, divided
• 5 tablespoons olive oil, divided
• sea salt
• 1 large potato
• 1 bay leaf
• 2 tablespoons pine nuts
• 2 sprigs fresh rosemary
• 2 garlic cloves, minced
• 2 tablespoons lemon juice, divided
• freshly ground black pepper
• 1 "large pizza" ball of dough, or 3 pieces of naan
• 1 ball fresh mozzarella, sliced
• 1/2 cup aged Gruyere cheese, shredded
• 1 pinch chili flakes
• a few handfuls of arugula
• 1.5 tablespoons balsamic cream

1. Preheat your oven to 500F. If you have a pizza stone, let it heat up for about an hour before you plan to use it. (You can also use the bottom side of a baking sheet, which I did until recently. I let mine hang out in the oven for about 30 minutes before using it.)
2. In the meantime, prepare the other ingredients. Halve the onion, and cut each half lengthwise into thin slices. Heat 1 tablespoon of butter and 1 tablespoon of olive oil in a wide saute pan over medium heat. When the butter is gently bubbling, add the onions. Cook, stirring occasionally, until the onions are soft and deeply brown, about 40 minutes. If they start to look a little dry during cooking, add some water. Add a pinch of sea salt, to taste. (If you are short on time, you could always just saute the onions until they are soft. You can also make this ahead of time, and simply re-warm before use.)
3. While the onions are cooking, peel the potato and cut it crosswise into thin-ish slices. Move the potato to a Dutch oven, along with 1/2 cup of water, 1 tablespoon of butter and the bay leaf. Cover, and cook the potato over medium heat for about 20 minutes, or until the liquid evaporates and potato is "broken". Remove the bay leaf and discard. (This step can also be done ahead; re-warm.)
4. Toast the pine nuts in a pan over medium-low heat, shaking the pan occasionally, until they start to brown and smell toasty. (Can be done ahead.)
5. In another saute pan, warm 1/4 cup of olive oil. Add the rosemary, and then the garlic. Heat gently for about 20 minutes, or until you are ready to start the pizza. (Can be done ahead; store in the fridge overnight.)
6. Lift your preferred amount of sardines out of the oil. Filet them if you want, or move them whole to a large bowl. (You want some oil to cling to them.) Toss the sardines with 1 tablespoon of the lemon juice and a few turns of a pepper mill, and then set them aside. Reserve the sardine bowl.
7. After stretching out the dough to your liking, prepare the pizza on a floured pizza peel (or the floured back of another baking sheet). First, brush the rosemary/garlic oil lightly over the dough, particularly over the crust. Without over-loading the pizza, add the: caramelized onions, potatoes, mozzarella, Gruyere, chili flakes and the sardines.
8. Transfer the pizza the oven, and cook for about 5-8 minutes, or until the cheese is bubbling and starting to brown.
9. When the pizza comes out of the oven, top it with the arugula. Serve immediately.

white onion, unsalted butter, olive oil, salt, potato, bay leaf, nuts, rosemary, garlic, lemon juice, freshly ground black pepper, dough, fresh mozzarella, gruyere cheese, chili flakes, arugula, balsamic cream

Taken from food52.com/recipes/16341-sardine-pizza (may not work)