Bring a large pot of boiling salted water to a boil, and drop in potatoes. Return to a gentle boil over medium heat, and cook for 12-15 minutes, until tender enough to pierce with a fork. Drain in a colander, and transfer half of the potatoes to a food processor.
Heat oil in a large sauté pan over medium heat, and sauté shallots for 10-12 minutes, stirring frequently, until a deep golden brown. (Be careful—they go quickly from golden to burnt in the last minute or so.) Transfer to a paper towel. Set aside 2 tablespoons of shallots.
Add 2 tablespoons butter, milk, honey and soy sauce to the food processor with the sweet potatoes, and puree for 30 seconds, until smooth. Scrape into a bowl, and repeat with the remaining ingredients. Combine the two batches of puree, season with salt and pepper, and stir in all but the reserved 2 tablespoons of shallots.
Scrape into a serving bowl, and top with reserved shallots.