Step 1

Use a wire whisk or fork to combine the flour and salt in a large mixing bowl.

Step 2

In a medium bowl or measuring cup, combine the yeast, sugar and warm water. Set aside.

Step 3

Once the yeast mixture has become bubbly and foamy—about 10 to 15 minutes—stir in 2 tablespoons of the olive oil.

Step 4

Add the yeast mixture and the sourdough discard to the dry ingredients. Mix well with a fork or Danish dough whisk. Knead the dough in the bowl a few times to incorporate all the flour. The dough will be quite wet.

Step 5

Turn the shaggy dough out onto a floured surface and knead gently for 4 minutes until smooth. If the dough sticks, sprinkle a bit more flour on the work surface and on the dough as you knead it. Avoid adding too much additional flour as it will alter the texture of the dough.

Step 6

Grease the bowl with olive oil, return the dough to it, turn the dough upward to coat the entire ball and cover the bowl with a towel, plate or lid. Let proof for about 1 hour, or until the dough has doubled in size.

Step 7

Generously grease a 9- by 13-inch metal cake pan or glass baking dish with butter or vegan butter. Olive oil alone may not prevent your focaccia from sticking to the pan, whereas a barrier created by the solid fat will. After greasing the pan, pour in 1 tablespoon of olive oil and spread it evenly around the bottom.

Step 8

Punch down the dough and pull the edges toward the deflated center. Turn the dough out of the bowl and into the pan. Roll the dough upward to coat the entire surface in oil. This will prevent the dough from drying out as it proofs. Gently stretch the dough toward the corners of the pan. It won’t fill the pan at this point. Cover with an inverted baking sheet and refrigerate overnight for at least 8 hours and up to The dough will double in size. (See Note on same-day baking.)

Step 9

At the end of the cold proof, remove the pan from the refrigerator. Let it sit at room temperature while the oven heats up in the next step (about 15 minutes).

Step 10

Preheat the oven to 425°F. Just before baking, drizzle the remaining 1 tablespoon of olive oil over the dough and slather it across the top with your hand. Beginning in the center of the dough, gently press in your fingertips to dimple it, carefully stretching the dough toward the edge of the pan. Dimple and stretch in the opposite direction, filling the pan evenly. Try not to deflate the dough as you work. Lay toppings across the dough or press them gently into the dimples. Sprinkle the focaccia dough and toppings with salt.

Step 11

Bake at 425°F for 25 to 30 minutes, or until the focaccia is golden brown. Remove from the pan and cool on a rack for 20 minutes before slicing.