Put the ground beef in a medium size mixing bowl. Chop the oregano and mint and add to the bowl. Finely dice the onion and add to the bowl. Crack the egg into the bowl. Add the salt, pepper, and minced garlic to the bowl. Add in the rice. Slice the carrots into ¼" slices and reserve for later.
Mix the ground beef mixture really well and form the meatballs. I like to make mine about the size of a quarter in diameter. If you want your meatballs bigger, you may want to increase your pressure cook time by 1-2 minutes.
Add 4 cups of chicken stock to the inner pot of the Ninja Foodi or your pressure cooker and add in the raw meatballs. Put the pressure lid on and turn the valve to seal. Pressure cook on LOW for 7 minutes. When the time is up, allow the pot to natural release for 5 minutes and then manually release the remaining pressure.
While the meatballs are pressure cooking, make up the lemon sauce. Add 2 eggs to a medium mixing bowl. Juice the two lemons into the bowl and whisk to combine the eggs and lemon. Add the cornstarch and whisk to combine. Make sure there aren't any clumps of cornstarch.
When the pin in the back drops, open the lid and remove the meatballs with a slotted spoon. I like to use the Scoop 'N Drain from Pampered Chef because it holds a lot of meatballs at once.
Add in the sliced carrots and turn the Ninja Foodi on high Sear/Sauté to cook the carrots. This only takes about 5-10 minutes.
Temper the egg and lemon mixture by adding a ladle full of the hot stock to the egg and lemon mixture and whisking. Repeat this 2-3 times, stirring in between each addition of stock.
Slowly add the lemon and egg mixture to the soup, stirring constantly. As it cooks, the sauce will thicken. Turn the heat down to medium and stir until the soup reaches the desired consistency. I like it about the consistency of a creamy tomato soup.
Return the meatballs to the soup and add in the spinach. Turn the Ninja Foodi off and stir in the spinach. The heat from the soup will cook the spinach perfectly.
Serve & Enjoy!