1. Place bread in a small bowl and pour enough milk over to wet each piece.
Let soak for 5 minutes. Using your hands, gently wring out the excess liquid and place the bread into the bowl of a food processor.
2. Add beef mince, lamb mince, onion, garlic, egg yolk, herbs and spices to the food processor.
Add the zest of one lemon and the juice of half a lemon. Pulse the mixture on low until combined and slightly fluffy in texture.
3. Transfer the meatball mixture to a bowl, cover with a towel and let rest in the fridge for about an hour.
4. Heat up your oven for 15 to 20 minutes with the flames on high to allow the baking stone to get hot, aiming for around 300 °C.
You can check this quickly, accurately and from a safe distance with an infrared thermometer.
5. Remove the meatball mixture from the fridge and form into 2.
5-centimetre balls. If the mixture is sticky, dampen your hands with water. Place meatballs on a baking sheet or plate.
6. Preheat a cast-iron skillet in your Ooni on high heat for 3 minutes.
Carefully remove the skillet from the oven with gloves on, then reduce the flames to low (aim for around 288 °C).
7. If the skillet is smoking, allow it to cool down a moment, then coat the bottom of the pan with a thin layer of neutral oil.
Using tongs, arrange the meatballs in the cast iron skillet in an even layer.
8. Return the skillet to the oven and cook for 3 minutes.
Remove the skillet from the oven and rotate the meatballs for even browning using tongs. Rotate the skillet 180 degrees and return to the oven for an additional 3 minutes or until meatballs are browned on at least two sides. Drain meatballs on a paper towel.
9. Serve and enjoy with a side of tzatziki sauce, or use them on a Greek Mezze Pizza.
