Remove the rind from the flesh from the lamb, leaving a thin layer of fat on it. Wrap the end of the bone wrap in foil to prevent scorching. Place the fatty side of the lamb in a hot pan and sauté with a little hot oil then remove and let them cool.
Mix the 2 tbsp Kerrygold Irish butter with the mustard. Spread the mixture on the fatty side of each lamb rack. Then mix the rest of the herbs crust and knead. Divide in two and press on both sides of the finished lamb and press firmly. Put the lamb racks into a roasting pan. Preheat the oven to 375°F degrees and cook for about 20-25 minutes until the meat is then pink and juicy. Let rest briefly before cutting into four parts.
Put the peas and mint in a food processor and blend until it’s a smooth paste. Mix in the cream and Kerrygold butter and then fold mixture into the potatoes and mash. Season to taste with salt and black pepper. Continue to stir at a low heat until everything is hot.