Preheat your oven to 400°F (200°C).
Halve the cherry tomatoes and mince the garlic clove.
In a small oven-safe skillet or ceramic baking dish, toss the tomatoes and garlic with the olive oil, sea salt, black pepper, and dried oregano.
Place the dish in the oven and roast for 10 minutes until the tomatoes begin to blister and release their juices.
Remove the dish from the oven and stir in the baby spinach until it is just slightly wilted from the residual heat.
Pour the liquid egg whites evenly over the roasted vegetable mixture.
Carefully crack the 3 whole eggs on top of the egg whites, spaced evenly apart, ensuring the yolks remain intact.
Sprinkle the crumbled feta cheese over the top of the entire dish.
Return to the oven and bake for 10 to 12 minutes, or until the egg whites are fully opaque and set, but the yolks are still slightly soft.
Remove from the oven and let rest for 2 minutes before serving directly from the dish.