do a rough chop of the sweet potatoes and peel as preferred - you can keep most of the skins on but take off any coarse bits as you chop them up
boil in salted water until soft
mash, then let cool substantially
preheat the oven to 375
beat the eggs, milk, butter, vanilla, and brown sugar a bit, then pour into the pot with the mashed sweet potatoes and whip
pour/dollop out into a baking dish and smooth out
whisk the topping ingredients, less the walnuts, and then fold in the nuts (chopped relatively well)
spoon over the top of the sweet potatoes
toss in the oven uncovered for 30-40 minutes, until crispy and caramelized on top