Clean the black beans: rinse them and pick out any stones or bad beans. Once done, set aside.
Set your Instant Pot to Sauté. Add the olive oil and wait for 5 minutes.
Once the olive oil is hot, add the onion, the diced bell pepper and the salt. Cook and stir for about 5 minutes, or until softened.
Add the minced garlic and then sprinkle in the cumin, dried oregano and bay leaves.
Cook and stir for 1 minute, or until softened.
Add the beans, water and stir.
Cover and make sure to seal the Instant Pot. Cook on HIGH pressure for 35 minutes.
When the timer goes off, allow the steam to release naturally and then remove the lid.
In a large skillet over medium heat, add the ground beef and add salt to taste.
Use a spatula to break the meat into small pieces and cook until brown.
Add the beans over the cooked meat and combine. Make sure to add some broth from the beans to cover the meat. Cook for 15 minutes over high heat and until all the water is consumed. Then, remove the bay leaves and discard them. Let it sit.
Cut the top of the bell peppers to form a lid. To make it look like a pumpkin, follow the curves of the upper side or the peppers. Carefully, cut the veins inside the peppers and remove it along the seeds using a spoon.
Using a small knife or a cutting tool with a sharp and thin blade, cut the faces on your bell peppers. Avoid knives or cutting tools with wide blades in this process. Fresh bell peppers are very moist and easy to break by hand, for this reason, remove the cut pieces slowly to avoid breaking details in your bell pepper's faces like teeth.
When the faces of your bell peppers are cut, it is time to fill them with the bean-meat mixture. Using a spoon, fill each bell pepper with the bean mixture at ⅔ of its capacity.
Then, top your bell peppers with mozzarella cheese. Preheat the oven to 350 °F.
Move your bell peppers to a baking sheet with lined parchment paper and place them inside the oven. Bake at 350 °F for about 25 minutes, or until warmed through and peppers soften.
Remove the bell peppers from the oven and let them sit for 10 minutes before serving.
To serve, sprinkle dried parsley over the top of the melted mozzarella cheese. Enjoy!