Place an oven rack in the center of the oven. Preheat the oven to 400 degrees F.
For the filling: In a large saucepan, heat the oil over medium-high heat. Add the pancetta and cook, stirring occasionally, until brown and crispy, about 8 minutes. Pour the pancetta and any cooking juices onto a paper towel-lined pate. Add the butter, shallots, carrots and thyme to the saucepan. Season with 1/4 teaspoon salt and 1/4 teaspoon pepper. Cook until the carrots are tender, 6 to 8 minutes. Stir in the flour and cook for 1 minute. Increase the heat to high. Add the chicken broth and scrape up the brown bits that cling to the bottom of the pan with a wooden spoon. Cook until the mixture thickens, about 3 minutes. Add the cooked pancetta, heavy cream, turkey, peas, corn, and the remaining salt and pepper. Simmer for 3 minutes until heated through. Using a ladle, fill the ramekins with the mixture.
For the crust: In a food processor, pulse together the flour, cornmeal, salt, baking powder, and baking soda. Add the butter and cheese and process until the mixture resembles coarse meal. With the machine running, add 1/3 cup buttermilk and the oil. Process until the mixture begins to form a ball, adding extra buttermilk, 1 teaspoon at a time, if needed. On a lightly floured work surface, roll out the dough into a 10-inch diameter circle, about 1/4-inch thick. Using a 3-inch round cookie cutter, cut the dough into 6 circles and place on top of the filling.
Bake until the crust is golden and the filling is bubbling, 20 to 25 minutes. Cool for 5 minutes before serving.