1 tbsp. olive oil
1 medium yellow onion, diced
1 c. peeled and chopped carrots (about 3 medium)
1 c. chopped celery (about 2 large stalks)
14 oz. can diced tomatoes, drained
3 cloves garlic, minced
2 tsp. tomato paste
2 bay leaves
1/2 tsp. dried thyme
14 oz. can chicken broth
14 oz. can beef broth
large bunch Swiss chard, center stems removed, chopped
1 tbsp. flour
1 lb. cooked, shredded beef from a chuck roast
1 c. peeled parsnips, cut into chunks
2 c. peeled potatoes, cut into chunks
2 c. peeled butternut squash, cut into chunks
1 tbsp. butter
Heat the olive oil in a large pot over medium-high heat. Add onion and saute 5 minutes. Add carrots, celery, tomatoes, garlic, tomato paste, bay leaves, and thyme. Saute until partially tender then add broths and bring to a boil. Lower heat and simmer until vegetables are very tender, about 15 minutes. Stir in Swiss chard and cook until wilted, about 5 minutes.
Put the flour in a small bowl, scoop a bit of the hot broth into the bowl, and whisk until smooth. Add to the pot and stir in the beef. Bring to a boil and season with salt and pepper. Remove from heat.
While the filling is cooking, bring a large pot of salted water to a boil. Add parsnips and cook 2 minutes. Add potatoes and squash and cook until very tender, about 10 minutes longer. Drain, reserving 1 cup of the cooking liquid. Return vegetables to the pot and use a hand mixer to puree the vegetables with the butter. Add reserved cooking liquid a bit at a time until everything is smooth.
Preheat the oven to 375º. Pour the filling into a rectangular baking dish. Spread the warm topping over and bake until the filling bubbles at edges and the topping begins to brown, about 30 minutes. Let cool slightly and serve.