In a bowl, mix together beef chuck, lemongrass, garlic, paprika, Red Boat Fish Sauce, brown sugar and a dash of cloves. Let marinate for 30 minutes.
On a baking sheet, add ginger, onion half, cloves and star anise. Broil on high, carefully watching the cloves and star anise. Remove the cloves and star anise immediately once they’re toasted and fragrant. Continue broiling the ginger and onion until charred and toasted.
In a large pot, sear beef chuck on all sides. Remove beef chuck and set aside.
In the same pot, add mushrooms and sauté until softened. Add oil as needed, onions and ½ teaspoon of salt. Sauté until softened. Add tomato paste and saute until lightly brown. Add the seared beef chuck back into the pot along with the toasted spices, ginger, onion, lemongrass thirds, beef broth and coconut water. Bring to a boil and simmer uncovered for 1 hour or until beef chuck is tender. Season with 1-2 teaspoons of Red Boat Fish Sauce.
Remove spices, lemongrass, onion and ginger from the pot and discard. Add in the carrots and more coconut water if needed. Cover and simmer for 15-20 minutes or until carrots are tender.
To make the mashed potatoes, bring a pot of water, potatoes, garlic cloves and lemongrass to a boil. Reduce to a simmer and continue simmering until potatoes are tender when pierced with a fork, about 15 minutes.
Discard garlic cloves and lemongrass and drain potatoes. Add the potatoes back into the pot and use a ricer or potato masher to mash the potatoes. Mix in butter, warm coconut milk and salt to taste. Enjoy mashed potatoes topped with lemongrass beef stew.