Chop the mushrooms finely and mince or chop the garlic too.
Heat a cast-iron skillet and add in some oil or butter.
Cook the mushrooms until they are well browned.
Turn down the heat to medium and add the garlic. Cooking and stirring for a minute or so just until they release their aroma. Do not colour them.
Remove the pan from the stove, put the fried mushrooms and garlic in a separate bowl and let it cool to room temperature.
Meanwhile, chop some parsley with a sharp knife.
When the Mushroom mix has cooled down, add it to the room temperature butter along with the chopped parsley and seasoning if you are seasoning it.
Once you have mixed it all together. Store it in the fridge wrapped up or do the following for easy portioning.
Lay a piece of parchment flat on the table. Place the butter on the parchment and place another piece of parchment on top. Roll out to 5mm thick and close the parchment so that you have a thick envelope of garlic butter. Store in the fridge until needed.
Preparing the chicken
Cut the chicken horizontally but do not cut it completely through. This is called butterflying.
Once cut, place between two layers of plastic wrap or parchment lightly oiled. Gently roll out with a rolling pin.
Cut a piece of the garlic butter you made and place in the middle of the rolled out chicken breast.
Fold it close and make sure all the sides are covered and there is no butter sticking out anywhere. Otherwise, it will escape while we fry the chicken. Not what we want.
Prepare a little breading station. You will need three bowls. One for seasoned flour, one for seasoned beaten egg mixed with equal amount of water or milk, and one with breadcrumbs. To season the flour and eggs simply add some salt and pepper.
Cover the chicken with flour first then dip in the egg mixture and then into the breadcrumbs. Go back into the egg mixture and one last time into the breadcrumbs. This is called a double breading. Surprise surprise.
Place the kiev on a baking sheet or plate ready for frying or baking. You could also freeze it at this point if you are prepping ahead for another day.
Cooking and serving
Heat the oven to 180°C or 365°F. We will finish cooking the chicken in the oven to make it easy for the average home cook. If you are a confident cook then go ahead and fry it till done on the stove.
Heat a suitably sized skillet and add frying oil so that it is 1 inch or 2,5cm deep. Measure the temperature with a thermometer so that it's 180°C or 356°F. Regulate the temperature of the oil by turning the higher or lower.
When the oil is hot, carefully and away from you, place the kiev into the hot oil. Cook it on one side until it has a nice golden colour and then flip cooking on the other side too.
Once nicely browned on both sides, place onto a baking tray and into the preheated oven for 5 minutes. Check the internal temperature by sticking the thermometer needle into the top of the kiev but not going all the way into the centre as the butter will run out. When it reads above 65°C or 140°F remove and let it rest for 5 minutes. If it's not there yet give it more time.
Season with salt and pepper. Serve immediately.
Notes
Store airtight in the fridge for 4 days or 3 months in the freezer.
Use your favourite store-bought breadcrumbs like panko or make your own by drying out old bread and blitzing in a food processor.
You can make a mini kiev by using quail breasts. Make sure to remove the tender or small fillet whether using chicken or quail.