In a large bowl, combine whole wheat flour, white flour, lukewarm water, and yeast. Let it rest for 30 minutes to an hour.
Add 1 and 1/2 teaspoons of salt and olive oil to the mixture. Let it rest for another 30 minutes.
Wet your hands thoroughly with water. Stretch and fold the dough 4-5 times.
Repeat the process every 30 minutes over 2 hours.
Leave the dough in the fridge overnight. If you are in a hurry, you can leave the dough to ferment at room temperature for 2-5 hours before baking.
Bring a wide baking pan and oil it generously with olive oil using a brush.
Transfer the dough to the oiled baking pan and gently stretch the dough to fill the pan. Proof at room temperature for another 1-2 hours until fluffy. You will see bubbles when it's ready.
Preheat the oven to 200°C (390°F). Dimple the dough using oiled fingers.
Drizzle the dough generously with olive and sea salt flakes.
Add toppings of your choice to the dimples. I like to add red onion slices, olives, cherry tomatoes, and oregano.
Place the pan into the oven and bake for 30 minutes until the outer layer is golden brown.
Take the focaccia out of the oven once done. Let it cool for 30 minutes.
Enjoy!
