Preheat the oven to 375°F (190°C) and prepare an oven-proof baking dish.
Cook the chicken: In a deep pan, heat olive oil over medium-high heat. Add the chicken and sauté for 2–3 minutes with a pinch of salt, pepper, and paprika.
Add vegetables: Stir in the onions and leeks, cooking for about 5 minutes. Add the bacon and spinach, then cook for another 2–3 minutes until everything is well combined.
Make the sauce: Pour in the heavy cream and whisk in the eggs. Once the cream starts bubbling, stir in the cheese and season again with salt, pepper, and paprika.
Bake: Transfer the mixture into the prepared baking dish and bake for 10–15 minutes, or until golden brown on top.