Heat the olive oil in a skillet over medium heat. Once hot, add the finely diced onion and cook for 2 minutes, stirring occasionally, When it starts to soften, add the garlic and continue to cook until golden brown and soft. Set aside to cool.
Heat oven to 220 C (425 F). Line baking pan with parchment paper and set aside.
In a large bowl, place all the ingredients (including the sauteed onion/garlic mixture). Knead with your hands (great time to use rubber gloves) until thoroughly combined. Roll into meatball sized balls and place each ball on the parchment lined baking sheet.
Bake for 20 minutes, stirring the meatballs around halfway through. You'll bake until you cut into one and you see it's cooked throgh and the outside is golden brown.
Use immediately, or store for 3-4 days in the fridge or 3-4 months in the freezer. To freeze, first freeze them on a baking tray until they are frozen then place them in a freezer bag to avoid sticking.