In large saucepan (soup pan) combine 3 cups broth, lentils, and barley and yeast extract. Simmer for 30 min.
Twice rinse potato slices in water to remove starch. Add to large saucepan plus 1/2 cup broth. Simmer 25-30 minutes until tender and pieces fall apart and liquid is absorbed. Mash with butter and milk or half and half until fluffy.
Saute onions in medium saucepan adding garlic near end. Add 1 1/2 cups broth, carrots and walnuts. Cook until tender, about 15 min. Combine flour and water and add to carrot mixture, simmer until thickened.
Add carrot mixture, peas, tomato paste, soy sauce, Worcestershire sauce, and salt and pepper to lentils and barley.
Bake in 375 deg oven for 30 min. adding shredded cheese to top during last 15 min.
Serves: 8 Total cook time: 1hr 15min
Source: Allrecipes Vegetarian Shepherd's Pie II