Preheat your oven to 475˚F (245˚C).

In a large bowl, combine the white whole wheat flour, all-purpose flour, salt, instant dry yeast, and garlic salt. Stir well to combine.

Add 0.5 cups of lukewarm water and mix. Then, pour in another 0.25 cups of water and continue to mix. Add the remaining water if needed until all the flour is absorbed and a shaggy dough forms.

Turn the dough out onto a lightly floured surface and knead for 1 minute.

Lightly oil a large bowl. Place the dough in the bowl and turn it to coat with the oil.

Cover the bowl with a kitchen towel and let the dough rise in a warm place for about 30 minutes. (Tip: placing it on top of a warm stove can speed up the process to around 20 minutes).

Gently punch down the dough and knead it again briefly on a lightly floured surface.

Roll or stretch the dough into a rectangular shape, about 0.25 inches thick, and place it on a lightly greased baking sheet.

Dimple the dough all over with your fingertips.

Brush the surface of the dough generously with olive oil. Sprinkle with garlic powder, dried oregano, and dried rosemary.

Bake for 10 to 20 minutes, or until the focaccia is golden brown and reaches your desired crispness.

Remove from the oven and let the focaccia cool on the baking sheet for about 10 minutes.

Slice the focaccia into wedges or squares. Serve warm with your favorite dipping sauce, or use as a base for sandwiches.