For the meatloaf, preheat oven to 375 degrees. In a medium bowl, combine the bread cubes and milk, and toss. Let sit until the milk is absorbed, about 10 minutes. Squeeze out any excess milk, and put the squeezed-out bread in a large bowl.

To the large bowl, add the turkey, eggs, panko, grated cheese, bell pepper, scallions, parsley, and salt. Mix with your hands to distribute the ingredients evenly.

Brush a large roasting pan with 1 tablespoon of the olive oil. Form the meat mixture into a loaf in the roasting pan, and brush with the remaining tablespoon olive oil.

Loosely cover the roasting pan with foil, and bake until the meatloaf is set on the outside, about 40 minutes. Uncover, and bake until cooked through (the center of the loaf will read 165 on a meat thermometer), about 45 to 50 minutes more.

Let the meatloaf rest, covered with foil to keep warm, while you make the sauce.

For the sauce, in a large skillet, heat the olive oil over medium heat. Add the shallots, and cook until they begin to soften, about 4 minutes.

Add the mushrooms and sage, and season with the salt. Cover, and let the mushrooms sweat until tender, about 10 minutes.

Uncover, and increase the heat to reduce away the liquid and brown the mushrooms, about 1 to 2 minutes.

Clear a space in the pan, and add the tomato paste. Cook and stir the tomato paste in that spot until it is toasted and darkens a shade or two, about 1 minute.

Stir the tomato paste into the mushrooms, and add the wine. Simmer to reduce the wine by half, then add the stock. Simmer to blend the flavors and reduce the stock a bit, about 5 minutes.

Right before serving, whisk in the butter until the sauce is smooth. Stir in the parsley.

Slice the meatloaf, and serve the sauce on the side.