Drain and rinse jackfruit. Pat dry. Remove and discard the core from the jackfruit pieces, it looks kind of like a seed. Toss the rest in a mixing bowl with 3 tablespoons of olive oil and a big pinch of salt.
Preheat a cast iron grill over medium heat. When pan is hot, place jackfruit in as much of a single layer as possible. You will need to do this in two batches. Grill for about 5 minutes, until charred and smoky, then use a thin metal spatula to toss and grill again for 3 more minutes. Transfer to a bowl and set aside to add back later.
In the same mixing bowl, toss pearl onions in 1 tablespoon olive oil and a pinch of salt to coat. Place on the hot grill. Let cook until softened and charred in some spots, flipping occasionally, about 15 minutes.
In the meantime, reheat a 4 quart pot over medium high heat. Saute shallots and a pinch of salt in remaining 2 tablespoons olive oil until translucent, 5 to 7 minutes. Add garlic and carrots, saute for about 5 more minutes.
Add thyme, bay leaves, smoked paprika, and salt and toss around for a minute.
Add wine to deglaze the pan, scraping the bottom with a wooden spatula, and bring to a boil. The liquid should reduce in about 3 minutes. While it’s reducing grind in ample amounts fresh black pepper.
Add lentils, porcinis, vegetable broth and tomato paste, cover and bring to a full boil for 5 minutes or so. Lower heat, leave lid ajar for steam to escape, and simmer until lentils are tender, about 30 minutes.
In a measuring cup, mix the flour into the water with a fork until no lumps are left. Slowly add the water/flour slurry to the pot, mixing well. Let cook for about 10 minutes, stirring often. If it appears too thick, thin with a little water.
Mix in the jackfruit and pearl onions and heat through. Shut off heat and let the stew hang out for about 15 minutes, for flavors to marry. Serve with mashed potatoes and garnish with parsley.