Preheat the oven to 350°F (175°C).
Peel and cube the sweet potatoes. Place them in a large pot and cover with water. Bring to a boil over medium-high heat, then reduce to medium heat and cook for 12-15 minutes, or until the potatoes are fork-tender.
While the sweet potatoes cook, get the pecan topping made. In a medium food mixing bowl, combine the room temperature vegan butter, brown sugar, flour, and salt. Mix until a crumbly texture forms. Stir in the chopped pecans until evenly distributed.
Drain the potatoes and return them to the pot, or to a food processor if you have one. Add the plant-based milk, molasses, brown sugar, maple syrup, melted vegan butter, ginger, cinnamon, cardamom, coriander, cloves, and salt to the sweet potatoes. Mash until smooth and creamy.
Transfer the mashed sweet potatoes to a lightly greased baking dish, spreading them evenly. Sprinkle the pecan topping evenly over the mashed sweet potatoes.
Bake in the preheated oven for 30-35 minutes, or until the topping is golden brown and crisp.