Potato Bacon Frittata

Preheat the oven to 350 degrees.

Heat the olive oil in a medium (10-inch) oven-proof sauté pan with sloping sides over medium-low heat, add the bacon, and sauté over medium-low heat for 3 to 5 minutes, until browned.  Remove the bacon from the pan with a slotted spoon and set aside.

Discard all but 2 tablespoons of fat in the pan and add 3 tablespoons of the butter.   Add the potatoes and fry them for 10 to 12 minutes, until cooked through and lightly browned, turning occasionally.  Melt the remaining 5 tablespoons of butter in a small dish in the microwave.

Meanwhile, whisk the eggs in a large bowl, then stir in the ricotta, Gruyère, melted butter, milk, scallions, 2 teaspoons salt, and 1 teaspoon pepper.   Combine the flour and baking powder and stir into the egg mixture.

Add the bacon back to the pan and spread the potatoes and bacon out in a single layer.  Pour  over the egg mixture, smoothing the top.  Place the pan in the center of the oven and bake for 50 to 55 minutes, until the frittata is browned and puffed and a knife inserted in the middle comes out clean. Serve hot.

Set a fine mesh sieve over a deep bowl.  Dampen 2 pieces of cheesecloth with water and line the sieve with a double layer of the cheesecloth.

Pour the milk and cream into a stainless-steel pot and stir in the salt.  Bring to a full boil over medium heat, stirring occasionally.  Turn off the heat and pour in the vinegar.  Allow the mixture to sit for one minute until it curdles.  It will separate into thick parts (the curds) and milky parts (the whey).

Pour the mixture into the cheesecloth-lined sieve and allow it to drain into the bowl at room temperature for 20 to 30 minutes, occasionally discarding the liquid that collects in the bowl.  Transfer the ricotta to a bowl, discarding the cheesecloth and any remaining liquid.  Use immediately or cover with plastic wrap and refrigerate. The ricotta will keep refrigerated for 4 to 5 days.