Cook dried lentils in mushroom broth according to package instructions. Then remove from heat, drain, and set aside.
Pull 1 sheet of frozen puff pastry out of the box.
Combine the ground flax and water in a small bowl. Set aside for 10 min. It will thicken and gel up a bit. (This makes a flax egg).
Chop your onions, carrots, celery and garlic. Set aside.
Preheat oven to 400 degrees F.
Add vegan butter to a large skillet over medium heat. Then add celery and carrots. Sauté until softened about 4-5 minutes.
Add onions and cook another 3-4 minutes or until softened.
Add in garlic and the seasonings - onion powder, dried thyme, ground sage, smoked paprika, dried rosemary, nutmeg, salt and pepper. Stir together well and let cook for 1 minute.
Add in the tomato paste, soy sauce, vegan worcestershire sauce, maple syrup and liquid smoke and combine until the tomato sauce is fully incorporated. Remove from heat.
Into a large bowl, add the cannellini beans, and mash them down leaving some texture.
Into the bowl, add in that vegetable mixture from the skillet, the cooked lentils, sunflower seeds, breadcrumbs, nutritional yeast, and flax eggs. Combine together really well.
Shape the mixture into a log. * If it's too wet you can add more breadcrumbs or too dry add a splash of broth.
Lightly flour a surface and lay out the thawed puff pastry sheet. Sprinkle more flour on top. Roll out the puff pastry evenly to about 12x14 inches.
Move puff pastry to a piece of parchment paper and lay the lentil loaf on top of the pastry dough.
Brush the entire loaf that is visible with dijon mustard.
For sealing the puff pastry. Pick 1.Optional 1: Brush the sides of the pastry with dairy free milk. Roll up the puff pastry and cut off excess pieces. Making slits for air pockets in the top. Optional 2: Cut 1 inch strips on either side of the loaf on the longest sides, brush with dairy free milk, and criss cross strips on either side. Tuck the ends up and seal cutting off any excess*see video for visual
Brush the entire pastry with melted vegan butter.
Place parchment paper and loaf on a baking sheet and place into the oven for 30-35 minutes or until the top is golden brown. Brush with more melted vegan butter if desired.
Let cool for 5 minutes before slicing. Serve warm.