In a medium-sized pot, sauté the carrots and celery in vegan butter until tender.
Add in the lentils, water, bouillon, onion powder, garlic powder, vegan Worcestershire sauce, paprika, sage, thyme, and pepper.
Bring to a boil, then reduce to a simmer for 15-20 minutes, or until the lentils are tender and have absorbed the liquid. Add some salt or soy sauce if needed.
Turn off the heat, but leave the pot on the burner. Stir in the kale and sunflower seeds. Cover the pot for about 5 minutes, or until the kale has wilted.
Mix in the breadcrumbs. Let the lentil mixture cool until just warm, no longer hot. If the mixture is too hot, it will melt the puff pastry.
Pre-heat the oven to 400℉.
Once the puff pastry is thawed and pliable, you can start assembling your wellington.
Scoop the lentil mixture in the center third of the puff pastry in the shape of a log. Leave an inch of room on the edges. Make sure it's packed tightly.
Fold the sides of the puff pastry over the top of the lentil mixture, tightly. There should be about a half an inch of overlap. Pinch, seal and tuck the edges. Use water to help create a more secure seal.
Cover a baking sheet with parchment paper or a silicone baking mat. Place the wellington on it, seam-side down.
Score the pastry (directions in the post above) and then brush with the non-dairy milk (this will create a golden crust as an egg wash would.)
Bake for 30 minutes, or until golden brown.
Let cool for about 5 minutes, then use a serrated knife to cut slices.
Notes
*I recommend this vegetable bouillon or "no beef" bouillon. Both have rich, savory flavor perfect for this dish. **Worcestershire sauce typically contains anchovies, but there are several vegan brands - Annie's and the Kroger store brand are a couple. Just check labels. If you cannot find it, substitute with soy sauce or coconut aminos.