A 500 g sandwich loaf built at 10 percent fat, the lever that held its crumb softest on day 3 in our four-loaf comparison. One base formula, butter doubled, nothing else changed. Weighed in grams and stated in baker's percentages so you can scale it or move the lever into your own recipe. Bakes in a standard 9 × 5 inch pan.
Whisk the flour, sugar, salt and instant yeast in a large bowl.
500 g bread flour 4 cups + 2 tbsp , 20 g granulated sugar 1 tbsp + 2 tsp, 10 g fine sea salt 1 ¾ tsp
Add the lukewarm water. Mix to a shaggy dough with no dry flour left.
320 g water
Knead 8 minutes, by hand or on medium-low in a stand mixer.
Add the softened butter in three additions. Knead 4 more minutes, until the dough is smooth again.
50 g unsalted butter
Cover and rise 60 to 75 minutes at 75 °F (24 °C), until nearly doubled.
Deflate gently. Shape into a tight cylinder and place seam-side down in a greased 9 × 5 inch pan.
Cover and proof 45 to 60 minutes, until the dough crowns 1 inch above the rim.
Bake at 350 °F (175 °C) for 33 to 35 minutes.
Check the center with an instant-read probe. Pull the loaf at 196 °F (91 °C).
Turn out onto a rack. Cool at least 90 minutes before slicing.
Nathan's Tips
Add the butter late. Fat coats the flour proteins, so putting it in at the start slows gluten development. Eight minutes of kneading first, then the butter. The difference in loaf height is visible.
Do not swap the 50 g of butter for oil one-for-one. We tested how much fat, not which fat. Solid fats are the ones the published work supports here.
Store it bagged on the counter, sliced as you go. Cutting the whole loaf at once opens more surface. Past day 3, freeze in slices instead.