Preheat oven to 400°F and line a baking sheet with parchment paper. 

Spread cubed bread on baking sheet and toast for about 8 minutes until the bread is dry and very brown. Remove and set aside to cool.

In a large bowl toss together squash, leek, potatoes, 1/4 cup olive oil, 1/2 teaspoon salt and fresh ground pepper. Spread the vegetables on the baking sheet in a single layer and set aside.

Reuse the large bowl and place toasted bread, scallions, cranberries, apple, thyme, broth, milk, egg yolk, garlic powder, 2 tablespoons olive oil, 1/2 teaspoon salt and fresh ground pepper. Stir to combine and set aside.

Place a big piece of plastic wrap on a cutting board. Place the turkey breast on top and cover it with another big piece of plastic wrap. With a heavy pan or meat tenderizer, pound the turkey breast to an even thickness, around 1-inch. 

Remove the plastic wrap, season with 1/2 teaspoon salt and spread the stuffing evenly on the meat, leaving a half-inch border on all sides. Starting with one of the long sides, roll the turkey breast as tight as you can without pushing the stuffing out, like a jelly roll. Use some butcher’s twine to tie the roulade at 1-inch intervals.

Place turkey roulade on top of the vegetables on the baking sheet, seam side down. Sprinkle the turkey with 1/4 teaspoon of salt and some fresh ground pepper and drizzle with olive oil.

Roast until an instant-read thermometer inserted into the thickest part of the roulade registers 165°F, about 1 hour and 15 minutes to 1 and a half hours.

Remove the baking sheet from the oven and place a piece of foil on top of the roulade. Let rest for 15 minutes before cutting into 1-inch-thick slices. Serve with the roasted vegetables and a sprinkle of chopped parsley for garnish.