Process the mushrooms in the food processor by pulsing them 3 or 4 times. Do it in batches. Do not overprocess it, otherwise, the mushrooms will become a paste after cooked.
Add olive oil to a pan, when hot add the minced onion, stir for 5 minutes in medium heat or until golden, add the bay leaf and the garlic, stir for 40 seconds more.
Add the mushrooms, salt, and pepper and stir occasionally until they become golden brown. The mushrooms will release a lot of water at the beginning of the cooking process, that’s expected.
When the mushrooms are ready, add the lemon juice and the fresh parsley and turn off the heat.
In a pot on medium heat, add the vegan butter, when melted add the flour, stir for about 4 minutes, add the plant-based milk little by little, stir vigorously, repeat the process until all the milk is added to the pot.
Add salt, pepper, nutmeg, and nutritional yeast, mix to combine.
MAKE THE CROQUETTES:
Transfer the béchamel sauce to the mushroom pot, mix to combine, and adjust the salt.
Transfer the croquette mixture to a shallow plate, flatten the surface, cover with a cling film, allow it to cool, then put it in the fridge for at least 3 hours.
Put the all-purpose flour on a plate along with the salt, black pepper, garlic powder, and water, stir to combine. Put the breadcrumbs on another plate.
Remove the plate from the fridge, remove the cling film, cut the croquette dough into small rectangles, take one rectangle at a time from the plate and shape them into an oblong shape or a ball shape.
Shape all the croquettes first, only then you bread them, otherwise, you’re gonna have to wash your hands every time you shape a croquette.
Bread them by passing each croquette in the flour slurry, then the breadcrumbs, then the flour slurry, and the breadcrumbs again.
Put the breaded croquettes on a plate and put them in the fridge for another 25 minutes or in the freezer for 10 minutes before frying them. If you’d like to freeze them now’s the time.
Add the vegetable oil to a pan, allow it to reach the temperature of 185°C (365℉).
Remove the croquettes from the fridge, fry them in the hot oil, three or four units at a time until the croquettes are golden brown on all sides.
Remove them from the oil and place them in a cooling rack.
Serve them hot with mustard or your favorite sauce or dressing.