Preparation

• Heat the oven to 375°F. Heat the oil in a large, heavy saucepan or Dutch oven over medium. When hot, add the fennel, carrots, onions, garlic, red pepper flakes, 1/2 tsp. salt, and 5 grinds pepper. Stir, cover the pot, and cook until the vegetables become soft and aromatic, about 8 minutes. Add the squash and tomato paste, stir, cover, and let cook for another 10 minutes (watch to make sure the squash doesn’t burn). Uncover and add the tomatoes with their juices, the stock, lentils, lemon juice, and the remaining 1 tsp. salt and 8 grinds pepper. Tie together the sprigs of oregano and rosemary with kitchen twine; add to the pot. Raise the heat to high and bring to a boil, using a potato masher to break up the tomatoes a bit.
• Once the stew comes to a gentle boil, reduce the heat to medium low and cover, leaving the lid just slightly ajar. Simmer until the squash and lentils are tender, about 20 minutes. Uncover and stir in the chard leaves. Re-cover and cook until the chard is tender, about another 5 minutes. (If you end up with insufficient liquid, just add a bit more stock, and adjust the seasoning, if necessary.) Carefully remove and discard the herb bundle.
• While the stew is cooking, line two baking sheets with sides with parchment paper to cover. Sprinkle about half of the flour on a large, clean surface. Unroll the puff pastry and sprinkle with some of the remaining flour. Roll out the pastry to a rectangle roughly 11 x 16 inches. With a sharp knife, cut out 4 rounds, each roughly 5-1/2 x 6-1/2 inches. Place 2 rounds on each lined baking sheet. Gather the dough scraps into a circle, sprinkle with a bit more flour, and roll out. Form a fifth round and place it on one of the baking sheets (make sure to leave at least 2 inches between the circles). Sprinkle the 5 dough rounds evenly with 1 tsp. minced rosemary and 1 tsp. minced sage. Cut a few slits in each of the circles (to prevent the pastry from puffing up too much). If the pastry is still cold, proceed to the next step. If not, place the baking sheets in the refrigerator and chill the dough.
• Place the baking sheets with the cold pastry on two racks in the hot oven and bake until the dough circles are golden brown, puffed, and completely cooked through in the center, switching racks halfway through, 20 to 25 minutes total.
• To serve, ladle about 2 cups of stew into large, shallow soup bowls. Top each portion with a puff pastry circle, and—if desired—garnish with some of the remaining 1/2 tsp. minced rosemary and 1/2 tsp. minced sage. Serve hot.