Grate the onion and garlic into a medium size bowl; then add the Panko breadcrumbs and stir to combine. Set aside.
In a large bowl, add the ground beef and ground sausage. Break up the meat with a fork. Add the remaining ingredients and the reserved breadcrumb mixture. Use your hands to blend the mixture together. Do not over mix or the meatballs will be tough.
Scoop the meat mixture into 2-inch size meatballs, rolling them in the palm of your hand to create a smooth meatball. Transfer the rolled meatballs to a plate as you roll each one. Alternatively, scoop the meat and place on a sheet of parchment, then roll each one.
When all the meatballs are rolled, heat 2 tablespoons of oil in a large skillet set over medium-high heat, add the meatballs and brown, rolling them with tongs or a tablespoon to brown all areas. Brown the meatballs in 2 batches, transferring them to a paper towel-lined plate as they brown.
For meatballs and spaghetti:
In a large skillet, heat your favorite jar of marinara sauce, or make a homemade marinara sauce; then add the meatballs to the sauce.
Reduce the heat to low and simmer while cooking 16 oz. of spaghetti.
To Serve:
Place a portion of cooked, drained spaghetti into individual bowls and scoop sauce and several meatballs on each portion. Garnish with chopped parsley and serve with a dish of grated Parmesan cheese. Enjoy!
Notes
The secret to tender, juicy meatballs is to not over work the meat mixture. Mix with a light touch and only until blended.
Tip: Set a small dish of water at your work space to dip your fingers in occasionally when rolling the scooped meat into balls.
A medium-size cookie scoop will make uniformed meatballs of about 2-inches each
If you are planning to serve them in a marinara sauce they do not need to bee fully cooked as they will continue cooking in the hot sauce.
To bake the meatballs instead of frying, place a cooling rack over a foil-lined baking sheet and place the meatballs on the rack. Bake in a 400°F oven for 15-20 minutes, until tender and cooked through. Check one of the meatballs for doneness with a meat thermometer. They are fully cooked at 160°F.