Heat your frying skillet and oil to medium-high heat. To know when the oil is ready, sprinkle a pinch of flour into the oil. If it starts to bubble immediately, it's ready. If it takes a couple of seconds, it needs more time. You want the oil to be pipping hot.
While the oil warms up, mix all of the wet batter ingredients in a bowl and set aside.
Mix all of the dry coating ingredients in a separate bowl and set aside.
Prep the mushrooms: 1. Trim the mushrooms if needed by cutting off the rubbery part of the stem. Some may have them cut off already.2. If you see some soil on the mushrooms, carefully run them through some water for a quick rinse. 3. Make sure they are dry. Carefully pat with a paper towel if needed, especially if you rinsed them.4. Using your hands split the large mushrooms into smaller pieces. On average you can split them in half.
Place the mushrooms in the wet batter and cover them completely.
Carefully coat the mushrooms with the dry batter. You may want to place the mushrooms in the dry batter in two sections to avoid overcrowding.
Immediately after, add the mushrooms to the frying pan. Raise the heat to high to prevent the temperature from drastically changing.
Fry until crispy and golden brown for about 2 minutes with a maximum of 3 minutes. Turnover the mushrooms halfway. DO NOT overcrowd the frying pan.
Once fried, place on a cooling rack lined with paper towels to catch the excess oil.
Repeat until all the mushrooms are cooked. May take about 3 batches to fry completely.
Sprinkle with some finishing salt and oregano & DONE!