Heat 2 tablespoons olive oil in a 12-inch or larger regular or cast iron skillet over medium-high heat until shimmering. Add the onion, 1 pound ground turkey, 1/2 teaspoon of the kosher salt, and 1/4 teaspoon of the black pepper. Cook, breaking the turkey up into small pieces with a wooden spoon, until the turkey is cooked through, 6 to 8 minutes. Remove from the heat and let cool for 5 minutes. Meanwhile, place half of the Parmesan cheese, parsley, 1 container ricotta cheese, the remaining 1/4 teaspoon kosher salt, and remaining 1/4 teaspoon black pepper in a medium bowl and stir to combine.