First, bake the potatoes with their skins on in the oven at 190°C for 50 minutes. You need potatoes with floury flesh. This is the best way to ensure dry potato flesh at the end of cooking. Don't cook them in water!To obtain 500g of peeled flesh, you'll need at least 750g of raw potatoes with skin.
Wash and spin-dry the spinach leaves thoroughly. Put them in a small blender with 1/4 teaspoon salt and one or two tablespoons olive oil. The salt and oil will help to grind everything together.
The result should be a homogeneous purée.
Peel the warm potatoes, weigh out 500g and cut into chunks.
Mash with a potato masher (I can't remember where mine is!) or with a fork, which requires a little more work.
Pour in the spinach purée and mix well.
Then pour in the potato flakes and 100g flour. Potato flakes (basically mashed potatoes in a packet, but with nothing but dehydrated potato) will dry out the dough. Mix again.
Work the dough on a floured surface, then add the remaining flour (or more) until the dough barely sticks to your fingers.
There are two options for making the gnocchi. First of all, the little wooden board. Weigh out 10g balls, then roll them with your thumb on the small floured board.
Of course, you can also use a fork instead of the small gnocchi board. Alternatively, you can roll the dough into a sausage and cut into pieces!
It's best to let the gnocchi air-dry a little before cooking. To cook, place in boiling salted water, and when they rise to the surface, they're ready!