Preheat the oven to 375°F (190°C) and line an 8x12 inch baking pan with baking paper.
In a large mixing bowl, combine the Greek yogurt with the butter and half the amount of olive oil and whisk using an electric mixer at high speed.
Add the eggs one at a time while still beating with the mixer.
Fold in the almond flour, baking soda, xanthan gum, and garlic powder and knead to make a dough.
Transfer the dough onto the prepared baking tray and flatten with your hands.
Sprinkle with salt and rosemary and drizzle with the remaining olive oil.
Bake for 20-25 minutes, until slightly golden, and serve hot or cold.