Finely chop trimmed and cored fennel, peel and finely chop apples, finely chop celery and greens, then finely chop onion.  

Heat a large skillet over medium to medium-high heat and melt butter, add fennel, apples, celery and onions, season with salt and pepper and fresh herbs. Soften 7 to 8 minutes, add Calvados or brandy and stir, add white wine and let it absorb, stir in stuffing and add stock to moisten, cool in a bowl. Add an egg and sausage, if using, to cooled stuffing and mix together. 

Preheat oven to 425˚F with rack at center oven. 

Season inside the turkey breast with salt and pepper. Slather the turkey with Dijon and spread with stuffing, leaving a 1-inch border. Roll and tie the turkey breast with 4 to 6 strings. Lightly cover the skin with a little softened butter or EVOO and season skin with salt, coarse black pepper and poultry seasoning. Place in rack-lined roasting pan with a little bit of stock poured into the bottom to help keep the turkey breast moist or on a rack in rimmed baking sheet lined with parchment or foil. Roast 30 minutes then reduce heat to 350˚F and roast 1 hour more. Cool a bit then cut off strings.  

For the Gravy, heat a skillet or saucepot over medium to medium-high heat, add butter and melt, whisk in pepper and flour, whisk in stock and thicken, season with Worcestershire and salt. Add a little water to drippings in the roasting pan to loosen. Strain the drippings and whisk the liquid into the gravy. Remove from heat and add mustard.      

Slice roulade and ladle some gravy on to dinner plate, add 2 slices of roulade and sides of choice.