Wash sweet potatoes and roast in a in a 375°F preheated oven for 75-90 minutes, or until soft and starting to release some juice.
Add bananas during the last 15 minutes of cooking.
While the potatoes are cooking melt the 2 tablespoons of butter in a skillet and toast the pecans over a medium heat, tossing often.
All the butter will be absorbed and the nuts will be slightly fragrant.
Add a bit of salt and toss again.
After roasting let the potatoes cool enough to just handle them, peel and mash with bananas, melted butter, granulated sugar and honey.
Season to taste and add more sugar if desired (it will depend on your taste and how sweet the veggies are to begin with) In a small bowl mix the 2 tablespoons of cold butter into the brown sugar with your fingers, it'll be lumpy, but that's OK.
Spread the mashed mixture in a buttered baking dish, cover with pecans and sprinkle with brown sugar/butter combination. Bake at 350°F for 20-30 minutes until the topping is partially melted.