If you want to render the kidney fat cut it into small bits or mince it in a food processor.
Then, put it into a pot or big pan on low heat and wait for all the fat to get out while stirring occasionally.

You can see that it's done when there is clear fat on the bottom with crispy bits on top.

Now, you can remove these floating bits by pouring all content through a cheesecloth or fabric into another pot.
When the fat is cooled, pour it into mason jars and keep them in the fridge.

The method in this recipe works with nearly any type of meat, but best with cuts that contain fat & some gristle like beef shank or ham hock.

You may also enhance the sauce by deglazing the onions with red wine and let it cook for a minute before adding the meat stock.

Take care not to add too much salt, because the soy sauce is pretty salty already.

As a side dish, I like to simply cook some eggs or vegetables.

For a dairy free alternative, just replace the butter with coconut oil or lard.

I also added some mayonnaise and an avocado that I sprinkled with some salt & pepper on the side.

If you want a great sauce to go with your meatballs simply add about 150 gram cream to the pan with the remaining grease after frying and taking the meatballs out.
Then, let the cream cook on medium heat while stirring until it is reduced to your desired thickness. This works great with coconut milk/cream, too.
In case you don't want to use cream, slice 2-3 onions and cook them on low-medium heat in the remaining grease until they start to dissolve and everything thickens to a sauce.

You can modify this recipe to your taste by adding avocado, tuna, cheese or some crispy bacon bits.

The salad tastes best if you prepare it one day in advance and store it in the fridge over night.

You can check if the omelette is done by poking into it with a chopstick.
If you pull out the chopstick and it is clean your omelette is done. If there are moist residues from the eggs on the chopstick the omelette needs a few more minutes.

I used frozen spinach that I thawed in the microwave before adding it to the pan.
If you use fresh spinach you don't necessarily need to precook it, but give it a few more minutes of frying in the pan.

I like to eat this dish with some cream cheese on the side.

You may also add shredded cheese on top right before you put the pan into the oven.

As you can see on the picture I made a creamy sauce to go with everything, too. If you want to know how to make it check out this asparagus cream sauce recipe.