To make the meatballs, mix together the grated onion, nutritional yeast, salt, garlic powder, and almond flour in a large bowl until well combined. Add the meat, stirring until all the ingredients are well incorporated, clean hands work best, being careful not to overmix.

Roll the mixture into 1-inch balls. Set aside.

To a 6-quart slow cooker add the onion, celery, carrot, escarole (or kale), garlic, salt, stock, and water, stirring to combine. Add the meatballs and stir gently to combine.

Cover and cook on high for 4-5 hours or low for 6-7 hours.

At the end of the cooking time, whisk the egg in a small bowl. Uncover and pour the egg in while the soup is still simmering, stirring until ribbons form. Add the lemon juice and spinach, stirring to wilt the spinach.

Taste and add additional salt or lemon juice to taste.

Heat 1 tablespoon olive oil over medium high heat in a large pot or dutch oven. Add the onion and a pinch of salt, stirring to combine. Cook for 4-5 minutes or until the onions soften, stirring occasionally.

Add the carrot, celery, garlic, and salt. Cook for an additional 3-4 minutes, stirring occasionally.

Add the escarole (or kale), stock, water, and meatballs. Cover, bring to a boil, then reduce to a simmer.

Cook for 30-40 minutes or until the meatballs are cooked through and the vegetables are very tender.

Uncover and follow steps 5-6 above.