Preheat your oven to 375°F (190°C).

In a medium saucepan, combine equal parts water and milk and bring to a gentle boil over medium heat.

Gradually whisk in the polenta into the boiling liquid, stirring continuously for 5 to 7 minutes until it thickens.

Remove from heat and mix in butter, half of the grated cheese, salt, and pepper until everything is melted.

In a large skillet, sauté onions, garlic, and bell pepper in olive oil until soft, about 5 minutes.

Add the sliced sausages to the skillet and cook until browned, about 8 to 10 minutes.

In a greased baking dish, spread half of the creamy polenta, then layer with the sausage and vegetable mixture, followed by the remaining polenta and cheese.

Bake for approximately 20 minutes, or until the top is bubbling and golden brown.

Remove from oven and let cool for a few minutes before serving.