Prepare Baking Dish: Preheat your oven to 375°F (190°C). Lightly coat a 9×9-inch (23×23 cm) square baking pan with a thin layer of vegetable oil spray to ensure the bars don’t stick during baking.
Soak the Oats: Place the rolled oats in a small mixing bowl. Pour in the room temperature water and stir briefly to combine. Let the oats soak for about one hour, allowing them to absorb the water fully and soften.
Mix Wet Ingredients and Seasonings: In a separate medium bowl, whisk the eggs until they are just blended. Add the chopped parsley (or cilantro), minced garlic, salt, and black pepper. Stir well to evenly distribute the herbs and seasoning throughout the egg mixture.
Combine Oats with Egg Mixture: After the oats have softened, add them into the bowl with the egg and herb mixture. Stir everything together gently but thoroughly, ensuring the oats are fully coated and the mixture is evenly blended.
Bake the Oatmeal Bars: Transfer the mixture to your prepared baking pan. Use a spatula or the back of a spoon to spread the batter evenly across the pan’s surface. Place the pan in the preheated oven and bake for 25 to 30 minutes, or until the top turns golden brown and the bars feel firm when lightly pressed.
Cool and Slice: Once baked, remove the pan from the oven and allow the oatmeal bars to cool in the pan for about 10 minutes. This resting time helps the bars set properly. After cooling, cut them into bars of your preferred size.
Serve or Store: Enjoy the bars warm or at room temperature. For later use, store the bars in an airtight container in the refrigerator for up to five days. They also reheat well in an oven or microwave.