How to Make It
Season the veal with salt and transfer to a rimmed baking sheet. Refrigerate uncovered overnight. Bring the meat to room temperature 30 minutes before roasting.
Preheat the oven to 250° and set a rack in a large flameproof roasting pan. Arrange the veal racks back to back in the pan, with the frenched bones crisscrossed and pointing upward. Season with salt and pepper. Roast for about 1½ hours, until an instant-read thermometer inserted in the thickest part registers 100°. Increase the oven temperature to 500° and continue to roast for about 15 minutes longer, until the outside is browned and an instant-read thermometer inserted in the thickest part registers 120°. Transfer the racks to a carving board, tent with foil and let rest for 30 minutes. Set the roasting pan aside; do not wipe out.
In a medium saucepan, cover the potatoes with water and bring to a boil. Add 1 tablespoon of salt and simmer over moderate heat until tender, 15 minutes; drain. Using a ricer and working over a medium bowl, rice the potatoes.
In a food processor, pulse the 4 cups of peas with the 1 cup of mint, the lemon zest and 2 tablespoons of the cream until finely chopped. Season with salt and pepper.
In a large, straight-sided skillet, melt the butter in the remaining 3/4 cup of cream. Add the potatoes and cook, stirring constantly, until smooth and heated through, about 3 minutes. Fold in the pea mixture and lemon juice and season with salt and pepper. Cover and keep warm.
In a medium bowl, whisk the stock with the gelatin. Set the roasting pan on the stove over 2 burners. Add the shallot and cook over moderate heat, stirring occasionally, until softened, 5 minutes. Stir in the tomato paste and cook until deepened in color, 30 seconds. Add the stock mixture and bring to a boil over moderately high heat, scraping up the browned bits, until thickened slightly, 2 minutes. Strain the sauce through a fine-mesh sieve set over a heatproof medium serving bowl. Skim off any fat and season the pan sauce with salt.
Carve the veal into 8 chops and transfer to a platter. Drizzle the meat with some of the pan sauce. Transfer the mashed potatoes to a serving bowl and garnish with more peas and mint leaves. Serve the veal with the mashed potatoes, passing the remaining sauce at the table.