In a large bowl mix the starter, milk, sweetener of choice until dissolved.

Add flour and stir unti a shaggy dough forms

Cover and rest (autolyse) for 30-45 minutes.

Sprinkle on salt and knead or pinch into the dough.

Add softened butter or tallow in small pieces, kneading until fully incorporated and smooth.

Dough should be soft and slightly tacky, not sticky. Add tablespoon or two of flour if needed.

Cover and ferment at 75-78°F for 4-6 hours, perform stretch and folds 2-3 times during this period. (every hour or so)

It should rise about 50-75% and feel airy.

Turn the dough out, flatten gently, and roll up tightly like a jelly roll to form a loaf.

Place seam side down in a buttered or parchment lined 9x5 inch loaf pan. ( I used a pullman loaf pan for extra height).

Cover and proof for 2-4 hours at warm room temperature until the dough has risen about 1 inch above the rim and feel puffy ( if using a pullman pan let rise to level with rim of pan.)

1. You can also refrigerate overnight for an even richer flavor - just let it warm for 1-2 hours before baking)

Preheat oven to 375°F

Brush the top with milk or melted butter for a shiny crust.

Bake 35-40 minutes until golden brown and internal temperature is 195-200°F

Cool completely before slicing.