2 ¾cupsKing Arthur bread flour (390 grams), divided use
2tablespoonssugar
1 ¼teaspoonssalt
1tablespoondry milk powder
1tablespoonmelted or very soft butter
Instructions
Prep the Ingredients
Weigh out 290 grams of bread flour. Bring the mashed potatoes and egg to room temperature or slightly warm. Make sure butter is super soft or almost melted.
Make the Dough
Put the warm water in the stand mixer bowl. Add the yeast and let it stand for 5 minutes to proof.
Add the mashed potatoes and the egg to the bowl with the yeast, and stir with a scraper just until blended.
Add 2 cups of the flour (280 grams), sugar, salt, milk powder and softened butter and give the mixture a stir with your scraper just to bring it all together. Set the bowl on the mixer stand.
Begin mixing on low with the dough hook. Mix for about 3 minutes. The batter should be really sticky at this point. Remove it from the stand, scrape mixture into the center of the bowl and add half the remaining flour.
Set the machine back on the stand and knead until dough for another 2-3 minutes. It should still be sticky and clinging to both the hook and the side of the bowl at this point. Remove mixer from the stand.
This is the point where you have to judge how much flour to use. For me, I just dumped all the rest, using the full 390 grams. Knead for another 2 minutes. The dough should now be clinging to only the hook and not the sides of the bowl. It should be lumpy, soft, thick and not sticky. Knead on low for another 2 minutes just to build up the gluten a little more.
Put the dough in a greased (soft butter or oil are fine) bowl and roll it around so it's just a little bit slick. It should hold the ball shape and not spread at all this point. Cover with greased plastic wrap and set in a warm place for 1 hour or until doubled.
Meanwhile, butter up a 9x5 inch loaf pan. I recommend using a lot of salted butter so that the flavor of the butter will go into the crust.
Turn dough out onto a pastry mat. It should be smooth, soft, bouncy and not at all sticky. Pat it into a rectanglar shape then roll it up into a cylinder, starting from one of the short sides. Tuck it and shape into a loaf. Bounce it a few times on the mat to remove air bubbles. Set it in the greased 9x5 inch loaf pan.
Cover the pan with a piece of greased plastic wrap and let rise for about 30 minutes. It should rise to about the top -- that is the middle highest point of the dome should be just at the top of the loaf pan. Have faith that it will spring up in the oven and don't over-proof. Meanwhile, preheat the oven to 400°F.
You are going to bake the bread at 400 for 10 minutes, then drop the heat to 350 and bake for 20 to 25 more minutes.
So bake at 400 for 10, then 350 for another 25 or until the crust is a deep golden brown and the loaf sounds hollow when tapped.
Remove the bread from the oven and set the loaf pan on a rack to cool for about 10 minutes. If you want, you can brush it with butter and sprinkle some flaky salt on top. Turn it out onto the rack to cool. Let cool completely before slicing.
This bread should be firm enough for sandwiches, but also soft.
Notes
Sweet potato can vary when it comes to moisture. If using fairly dry roasted or microwaved sweet potato, you'll only need 140 to 150 grams. If using boiled and mashed sweet potato, use 160 grams.