Combine the flours, olive oil, salt, yeast, and water in a large container with a tight-fitting lid, or in a large bowl. Stir with a spatula until no dry spots of flour remain. Cover the container with the lid or bowl with plastic wrap and let sit for 20 minutes.

After 20 minutes, uncover the dough. Rub some olive oil on your fingers and place them underneath one corner of the dough. Lift and pull the dough to the opposite corner. Repeat with all 4 corners. Repeat the process with all 4 corners one more time. Cover the dough again and let sit for 20 minutes. Repeat this process (folding all the corners twice every 20 minutes) 3 more times for a total 5 complete rounds (the total rest time is 1 hour 40 minutes).

Place the dough in the fridge and let sit for 2 whole days.

Pour ⅓ cup of the olive oil into a 9 x 13-inch metal baking pan and swirl to coat; making sure to get all of the edges. Sprinkle 2 tablespoons of the wheat germ along the bottom of the pan and slide the cold dough on top. Press the dough down and outwards with stiff fingertips to fill the pan as much as possible. (There may be some empty corners.) Cover the pan with a towel and leave it in a warm place to proof until it is slightly poofy and has filled the pan, 1 to 1 ½ hours.

Preheat the oven to 500°F. Use stiff fingers to press into the dough, creating uniform dimples across the surface. Top with the remaining olive oil and wheat germ. Season with a sprinkle of flaky salt. Bake the focaccia until the top is deeply golden brown, charred in spots, and crunchy all along the base, about 30 minutes.

Transfer to a wire rack to rest for 20 minutes before slicing and serving.