Shepherd's Pie w/ Spinach Mashed Potatoes & Guinness

Step up your St. Patrick's Day game with this Guinness Shepherd's Pie! The
mashed potatoes are naturally dyed green with the addition of freshly puréed
spinach. The rest of the recipe is a more traditional vegetable medley. I
swapped out the meat for lentils in this vegetarian version of the dish.
Although you can easily sautée ground beef or lamb and use beef stock, instead
of vegetable stock. I also tossed in some Guinness because it's St. Patrick's
Day and you almost can't make food without beer today!