4 tablespoons extra virgin olive oil (EVOO), divided
1 small onion, chopped (about 1/4 cup)
2 cloves garlic, finely chopped or grated
1 box frozen chopped spinach (10 ounces), defrosted and wrung dry
A few grates of fresh nutmeg
1 1/2 pounds mixture of ground sirloin, pork and veal
Salt and ground black pepper
1 sprig rosemary
2 tablespoons butter
1 tablespoon flour
1/2 cup milk
3/4 cup ricotta cheese
1/4 cup grated Parmigiano Reggiano cheese
4 ciabatta rolls, split open
1 small bunch fresh spinach, thinly sliced
Place a medium size skillet over medium-high heat with two turns of the pan of EVOO, about 2 tablespoons. Add the onion and garlic to the pan and cook until tender, 4-5 minutes. Turn the veggies out into a large mixing bowl, then add the defrosted spinach and nutmeg and toss to combine. Add the ground meat and some salt and pepper to the bowl and mix to combine thoroughly. Form the mixture into four equal patties and reserve. Place a large skillet over medium-high heat with two turns of the pan of EVOO, about 2 tablespoons, and the whole sprig of rosemary. Add the burgers to the hot pan and sear until they are golden brown and cooked through, 4-5 minutes per side.
While the burgers are cooking, place a small pot over medium heat with the butter. Sprinkle the flour over the melted butter and cook, stirring frequently, for about 1 minute. Whisk the milk into the butter-flour mixture then stir in the ricotta, Parmigiano Reggiano and some salt and pepper. Bring up to a bubble and simmer until thickened, about 2 minutes.
Serve the burgers on the ciabatta buns topped with a hearty ladleful of cheese sauce and a sprinkle of shredded spinach. This is one of many "Yum-o!" recipes – it's good and good for you. To find out more about Yum-o!, Rachael's nonprofit organization, go to www.yum-o.org.