How to Make It
Whisk together first 7 ingredients and 1/2 teaspoon salt in a large saucepot over medium heat. Cook, whisking frequently, 12 minutes or until sauce thickens slightly.
Melt butter in a large nonstick skillet over medium-high heat. Add onion, celery, and garlic; sauté 5 minutes or until softened. Transfer mixture to a large bowl; let cool 10 minutes. Add remaining 1 teaspoon salt, beef, and next 4 ingredients. Mix thoroughly--by hand works best--and shape into 48 (3/4-ounce) balls.
Heat 3 tablespoons oil in a large nonstick skillet over medium-high heat. Add half of meatballs. Cook 5 minutes, turning to brown evenly. Remove from pan. Repeat with remaining oil and remaining meatballs.
Heat sauce in a large Dutch oven over medium-high heat. Adjust heat to maintain a very low simmer. Add meatballs (you may have to do this in 2 batches depending on the size of your pot), and simmer 7 minutes.