Preheat your oven to 180°C (350°F). Take a medium-sized bowl and set aside the cornmeal. Grease a round mould (such as a bundt pan) with oil, ensuring all sides are coated to prevent sticking. Arrange the sliced boiled egg and olives at the bottom and sides of the mould for a decorative finish.
In a large skillet, heat the olive oil over medium heat. Add the finely chopped onion and minced garlic, sautéing for 3-4 minutes until softened and fragrant. This base will build the rich flavors of your Cuscuz Paulista.
Add the chopped red bell pepper and diced tomatoes to the skillet, cooking for another 5 minutes. Stir occasionally until the vegetables are tender and the tomatoes release their juices. Season with salt and pepper to taste.
Incorporate the shrimp and/or shredded chicken (if using) into the skillet, mixing them with the vegetables. Cook for 3-4 minutes until the shrimp turns pink and the chicken is warmed through. If skipping the protein, you can proceed to the next step.
Stir in the drained peas, corn, and tomato paste, mixing well. Let it simmer for another 2 minutes. Add half of the chopped cilantro at this stage to infuse a fresh flavour into the dish.
Pour the chicken or vegetable broth into the skillet and bring to a gentle simmer. Slowly add the cornmeal, stirring constantly to ensure it absorbs the liquid evenly without forming lumps. Keep stirring until the mixture thickens and pulls away slightly from the sides of the skillet, about 5 minutes.
Once the mixture has thickened, taste and adjust the seasoning with more salt, pepper, or a touch of olive oil if desired. Remove from heat and allow the mixture to cool slightly, making it easier to handle.
Carefully transfer the couscous mixture into the prepared mould, pressing it down gently with the back of a spoon to ensure it is compact. Let the mixture sit for a few minutes before inverting the mould onto a serving plate. Garnish with additional cilantro, and serve the Cuscuz Paulista warm or at room temperature.