Ricotta Smothered Mushroom Burgers with Sweet OnionOlive Topping, Prosciutto, and Arugula

• 1/4 cup balsamic vinegar (eyeball it)
• 4 tablespoons extra-virgin olive oil (EVOO)
• Salt and freshly ground black pepper
• 4 large portobello mushroom caps
• 1 large red onion, thinly sliced
• 2 large garlic cloves, chopped
• 1 rounded tablespoon tomato paste
• 1 1/2 cups whole-milk ricotta cheese
• 3 tablespoons store-bought pesto sauce
• 1/2 cup chicken stock or broth
• 1/3 cup (a couple of handfuls) pitted kalamata olives, chopped
• 4 crusty kaiser rolls, split in half, toasted or notits up to you
• 8 thin slices prosciutto di Parma (optional)
• 1 small bunch of arugula, washed and trimmed of any thick stems

1. Preheat the oven to 450F.
2. In a shallow bowl, combine the balsamic vinegar, about 2 tablespoons of the EVOO, salt, and pepper.
3. Add the portobello mushrooms and toss to coat.
4. Arrange the mushrooms on a cookie sheet, gill side up.
5. Roast the mushrooms for 12 minutes or until tender and cooked through.
6. While the mushrooms are roasting, prepare the caramelized onion topping.
7. Heat a medium-size skillet over medium-high heat with the remaining 2 tablespoons of EVOO (twice around the pan).
8. Add the sliced red onions, garlic, tomato paste, salt, and pepper.
9. Cook the onions, stirring frequently, for about 8 minutes, or until nice and brown.
10. While the onions are caramelizing, prepare the ricotta cheese topping for the mushrooms.
11. In a bowl, thoroughly combine the ricotta cheese and the pesto.
12. Once the mushrooms have roasted for 12 minutes, remove them from the oven and divide the ricotta mixture evenly among the 4 mushrooms, spreading it onto the gill side of the mushrooms with the back of a spoon.
13. Return to the oven for about a minute, just to heat the cheese.
14. Add the chicken stock and chopped olives to the onions.
15. Turn the heat to high and continue to cook until the stock has reduced almost completely.
16. Arrange one cheese-topped mushroom on the bottom of each split roll.
17. Top the cheese with some of the caramelized onions.
18. Top that with 2 slices of prosciutto and some arugula.
19. Finish it off with a roll top.
20. Eat and enjoy!

balsamic vinegar, extravirgin olive oil, salt, portobello mushroom, red onion, garlic, tomato paste, wholemilk, storebought pesto sauce, chicken, couple, crusty kaiser rolls, parma, arugula

Taken from www.epicurious.com/recipes/food/views/ricotta-smothered-mushroom-burgers-with-sweet-onion-olive-topping-prosciutto-and-arugula-374256 (may not work)