Make the feta: Add all the dry ingredients to a bowl (almond flour to onion powder) and mix well.
Add the rest of the ingredients and mix well. Get your hands in there to press and knead into a dough. Taste and add more lime juice if needed. If the mixture is too crumbly, add a few drops of water at a time and press and knead then shape into a flat ball. Bake at 210 degrees F (100 C) for 30 mins. Chop into small pieces. Can be made ahead by upto 2 days, store refrigerated in closed container.
Cook the fettuccine according to instruction on the package, drain, rinse with cold water and set aside.
Meanwhile, heat oil in a skillet over medium heat. Add onions, a good pinch of salt and sugar and cook until golden. 6 to 8 mins. Stir occasionally. Add garlic and mix in and cook for 2 minute.
Add greens, oregano and red pepper flakes and olive oil and mix in. Cook until wilted.
Add the cooked pasta, salt, half of the cheese pieces and mix in. Add a good dash of black pepper. Taste and adjust flavor and salt. Add some lemon for additional tang. Add pasta water as needed to moisten the pasta, Cook for a minute to heat the pasta through. If the mixture is sticking, deglaze with a tbsp or so of water.
Plate the pasta and add some more of the cheese pieces per serving. Some extra virgin olive oil if you wish. Some pepper flakes for heat and fresh seasonal herbs. And watch it disappear!