Sparkling or still apple cider, alcoholic (hard) or nonalcoholic (sweet)--all work well in this recipe. Still cider produces a darker gravy with a slightly sweeter flavor.To make fresh breadcrumbs: Trim crusts from bread. Tear the bread into pieces and process in a food processor until coarse crumbs form. One slice makes about 1/3 cup.How to butterfly a turkey breast:1. Place the turkey breast on a cutting board. Starting on the rounded side, make a horizontal cut with a chef's knife, about halfway down, to within 1 inch of the other side.2. Open up the breast. Cover the breast with plastic wrap. Pound with a rolling pin or meat mallet to an even 1/2-inch thickness. Remove plastic wrap.3. Spread the stuffing over the breast, leaving a 1-inch borde
To prepare stuffing: Heat oil in a medium nonstick skillet over medium heat. Add onion and celery; cook, stirring often, until softened, 2 to 4 minutes. Add garlic and cook, stirring, for 30 seconds. Remove from heat and stir in breadcrumbs, parsley, thyme, sage, 1/4 teaspoon salt and pepper.
To prepare turkey: Remove skin from turkey breast and trim off fat. Butterfly the turkey breast (see Tip). Flatten the turkey breast. Spread the stuffing over the breast and roll the breast up into a cylinder. Secure with kitchen string.
Sprinkle the turkey roulade with 1/4 teaspoon salt and pepper. Heat 2 teaspoons oil in a large cast-iron or nonstick skillet over medium-high heat. Add the roulade and cook, turning from time to time, until browned all over, 5 to 7 minutes. Transfer to a plate. Add cider to the skillet and bring to a simmer, stirring to scrape up any browned bits. Add broth and bring to a simmer. Remove from heat.
Heat the remaining 2 teaspoons oil in a Dutch oven over medium heat. Add onion and cook, stirring often, until softened, 2 to 3 minutes. Add garlic and cook, stirring, for 30 seconds. Add the browned turkey roulade. Pour in the cider mixture, then add thyme sprigs (or dried thyme). Cover the pan and transfer it to the oven. e the roulade until it is no longer pink inside and an instant-read thermometer inserted in the center registers 170°, 45 minutes to 1 hour. Transfer to a carving board, tent with foil and keep warm.
To prepare gravy: Strain the liquid from the Dutch oven into a medium saucepan, pressing on the solids. Bring to a simmer over medium-high heat; cook for 2 to 3 minutes to intensify the flavor. Mix cornstarch and water in a small bowl; add to the simmering gravy, whisking until lightly thickened. Add sour cream, mustard and lemon juice, whisking until smooth. Season with pepper. Heat through.
Remove the string from the roulade. Carve into 1/2-inch-thick slices and serve with gravy.