Peel the potatoes and quarter. Place in a medium saucepan and cover with cold water. Set over high heat and bring to a boil. Once boiling, decrease the heat to maintain a simmer and cook until tender, approximately 10 to 15 minutes. While the potatoes are cooking, slice two carrots, toss with olive oil and roast until very soft, about 15 minutes. Put them in a food processor with a bit of broth and puree until smooth.
When the potatoes are done, drain them in a colander and add the milk to the warm pan. Return the potatoes to the saucepan. Mash the potatoes and then add olive oil until the potatoes stick together. Add salt and pepper and pureed carrots and continue to mash until smooth. These can be made ahead of time and refrigerated.
Add the peas (you don't need to thaw them if frozen) to the mixture and then spread evenly into an 11 by 7-inch glass baking dish. Top with the mashed potatoes, starting around the edges to create a seal to prevent the mixture from bubbling up and smooth with a rubber spatula. Place on a cookie sheet on the middle rack of the oven and bake for 25 minutes or just until the potatoes begin to brown. Remove to a cooling rack for at least 15 minutes before serving.
Recipe by forkbelly.com at http://forkbelly.com/vegan-shepherds-pie/