Take a large frying pan and place over a low/medium heat. Add the butter and leave to melt and foam for a minute or so.
2. Step
Next add the onions, mushrooms, garlic, salt and pepper. Slowly cook for around 10 minutes whilst continually stirring. You want the mushrooms to halve in size and the onions to be golden brown. Set aside.
3. Step
Take the celery sticks and peel the top ridged side to remove some of the stringy texture. Then cut into a small dice.
4. Step
Place the onions and mushrooms back onto the heat and add the diced celery. Stir for around a minute to warm through the celery and coat it with all the meaty flavour of the mushrooms and butter.
5. Step
Next add to mushroom and celery mixture to mash potato and mix to combine.
6. Step
Once combined take around a tablespoon of mixture and form into a croquette shape.
7. Step
Place the flour, eggs and breadcrumbs in three seperate bowls. To coat the croquettes, coat each croquet in flour, making sure to dust the excess off. Then dip in egg, then breadcrumbs. Place back into the eggs then back into the bread crumbs to give an extra thick and crunchy coating.
8. Step
Place a large pot over a medium heat and add the oil. Heat the oil to 180˚C (350˚F).
9. Step
Carefully place the croquettes into the oil and cook for 2-3 minutes or until golden brown. (Cook the croquettes in batches of 5-6 depending on how large your pot. If you cook too many at a time the oil may bubble over)
10. Step
Once cooked, drain kitchen towel to remove excess fat.
11. Step
Serve with an extra sprinkle of coriander and a sprinkle of sea salt.