A great dish for a crowd or a buffet - make 'em tiny and pile 'em into a crock pot to stay hot. Adapted from a recipe from Nigella Kitchen on Food Network. Serves 4 as a main course, or 8-12 as an appetizer.
Puree onion and celery to mush in food processor. Remove 2 tbsp of puree and set aside in a small bowl for the meatballs.
Heat oil in large skillet over medium heat until shimmering. (If you don't have garlic oil, saute 1 thinly sliced garlic clove in 2 tbsp oil until golden brown and very fragrant, about 3 minutes; remove and discard garlic before proceeding.) Reduce to medium-low, add vegetable puree and thyme, and cook, stirring occasionally, about 10 minutes.
Add tomatoes, water, sugar, salt and pepper. Bring to a gentle boil, then reduce to a simmer and let cook while prepping the meatballs.
Add all meatball ingredients to reserved vegetable puree. Mix gently to combine; avoid over-mixing to prevent the meatballs from being leaden and heavy.
Form mixture into approximately 50 meatballs (each should be about one heaping teaspoon). Once all the meatballs are formed, add them to the simmering sauce. Continue to simmer 30 minutes, or until the meatballs are cooked through.