Preheat the oven to 375°F (190°C). Wash the portobello mushrooms under cool water and gently remove the stems while being careful not to tear the caps. Pat them dry with a paper towel and place them on a baking sheet, gill side up.

In a skillet over medium heat, warm up the olive oil. Once it’s hot, add the diced green bell pepper and chopped onion, cooking until they are soft—about 3-4 minutes. Toss in the minced garlic and sauté for an additional minute, stirring frequently to prevent burning.

Add the diced tomatoes and spinach to the skillet. Cook until the spinach wilts down. Sprinkle in the sea salt, black pepper, oregano, and smoked paprika. Mix thoroughly so that the spices weave through the veggies, imparting flavor.

Remove the skillet from heat. Stir in crumbled goat cheese and shredded mozzarella. Mix until combined. Finally, fold in the panko breadcrumbs, which will add the necessary crunch when baked.

Generously spoon the cheese and vegetable mixture into each portobello cap. Don’t be stingy; pack the filling into the gills. This is where all the flavor resides!

Transfer the filled mushrooms back onto the baking sheet. Bake them for about 20-25 minutes in the preheated oven, or until the cheese is bubbly and the tops are golden brown.

Remove from the oven and let cool for a five-minute pause. Serve hot, perhaps with a fresh side salad or just on their own. Enjoy the depth of flavors that unfold with each bite.