makes 1 very large loaf

1 1/2 cups/375 ml warm water (110F/43C)

1 tablespoon/15 ml active dry yeast (about 1 packet)

1 tablespoon/15 ml sugar plus some for sprinkling

1/2 cup/82.5 grams if it’s active and bubbly, and 125 grams if it’s flat and fully fermented, room temperature

1 stick unsalted butter, melted (4 ounces/115 g)

1/2 teaspoon/5ml salt

2 1/4 – 3 1/4 cups/281g-406g flour all purpose flour

Preheat oven to 350F/176C/Gas Mark 4

In a small bowl pour 1/2 cup/125 ml warm water, stir in yeast and sprinkle with sugar. Let sit for 5-10 minutes until foamy (bloomed). In a large bowl whisk the remaining water sugar, melted butter with the bloomed yeast and sourdough starter, salt and 1 1/2 cups/180g flour until smooth. Using a wooden spoon stir in remaining flour 1/2 cup/63g at a time until a soft shaggy dough just clears the sides  when mixing. Remove dough to a lightly floured board and knead until elastic (about 2 minutes).  Place dough in a large well greased bowl. Cover with plastic wrap and let rise at room temperature until double in size (60 – 90 minutes). Gently deflate and put into a greased baking pan, covering loosely again with plastic wrap and let rise 60 more minutes. Place in a preheated oven on the center rack. Bake for 35-40 minutes. The bread should sound hollow when you tap the top. Remove from the oven and take the bread out of the pans to cool on a wire rack.