Heat the olive oil in a small frying pan over medium heat and cook the onions until they begin to soften, about 5 minutes. Transfer the cooked onions to a plate and set aside to cool.
Place the lamb in the bowl of a stand mixer. Combine the egg with the yogurt and add to the lamb. Add the cooled onions, almond powder, lemon juice, cumin seeds, cilantro, salt, and pepper to the bowl. Using a paddle, mix at low speed until the mixture is blended and starts to hold together.
Use a 4-cm round scoop to spoon out the meat mixture. Use one hand to form the portions into balls. Set aside.
Preheat the oven to 210°C.
Place some grapeseed oil in a frying pan to the depth of about 3 mm and set the pan over medium-high heat. Working in batches, brown each lamb ball quickly on two sides. Drain the browned meat well and arrange on a baking sheet.
Place the browned meat in the oven and cook until almost barely pink in the center, about 6 minutes. Remove the baking sheet from the oven and tent with foil. Set aside to rest for 5 minutes.
Drain the lamb balls on absorbent paper before serving.