Mushroom & Olive Focaccia Sandwich (Gluten-Free, Soy-Free, Dairy-Free)

1. Make the Focaccia (Skip if using store-bought): Preheat oven to 200°C (400°F). Mix flour, baking powder, and salt in a bowl. Stir in water, apple cider vinegar, and olive oil until a sticky dough forms. Spread onto a parchment-lined baking sheet, press black olives into the dough, drizzle with olive oil. Bake for 15–18 minutes or until golden and cooked through. Let cool and slice horizontally for sandwich halves.

2. Sauté the Mushrooms: Heat olive oil in a skillet over medium heat. Add sliced mushrooms and garlic, sauté until golden and softened (about 7–8 minutes). Season with salt, pepper, and herbs if using. Set aside.

3. Make the Spread (Optional): In a small bowl, mash avocado or stir dairy-free mayo with lemon juice, garlic powder, and salt.

4. Assemble the Sandwich: Spread the optional sauce on the bottom slice of focaccia. Pile on the sautéed mushrooms. Close with the top slice and press lightly. Serve warm or at room temperature.