You will need plenty of work surface so clear out a counter and make sure it's clean!
Peel potatoes and cut out all the dark spots. Cook potatoes until completely done and easily mashed. Mash each potato with a fork (or a potato ricer if you have one) util it looks like small coarse crumbs. (Don't over-mash it.)
When potatoes are cooled enough to be handled, place them in a mount on your work surface.
Add flour, salt and pepper over the top.
Make a well in the potato/flour mount, crack the egg in the middle and add tomato puree. Add all minced herbs on top.
Use a pastry scraper, or a metal spatula (or even a large knife, carefully) to work flour, potatoes and egg together, until incorporated enough to knead.
Knead the dough, adding a little more flour if the dough is too tacky, until smooth. Don't add too much flour, the dough should be moist but not sticky.
Split the dough into several, workable pieces and roll each into about ½ inch - thick, long rope-like logs. Cut each into about 1-inch pieces. You an shape each gnocchi if desired.
Gnocchi should be cooked right away or frozen.
To Cook The Gnocchi:
I prefer to sauté gnocchi with some onions and garlic. When gnocchi is nicely golden grown on each side, add about 1/4 cup of broth (for about 25 gnocchi pieces) and cook until broth is gone. Simple and deeelicious! You can also boil them in a pot of salted water. (Drop desired amount of gnocchi in it and once they float to the top, cook for about 2 more minutes.)
Freeze:
If you're not cooking the gnocchi right away, you should freeze them. Line large cutting boards with parchment paper. Spread out raw gnocchi on the paper (don't crowd them) and freeze for about an hour or two. (Set a timer!) Once completely frozen, place them into a freezer friendly, zip-top bag or divide them among several bags. Label, get as much air out as you can, seal, and freeze for up to 3 months. You can cook the gnocchi from frozen, no need to thaw them first.