1. Boil the potatoes and carrots until they are tender. Drain and set aside.

2. In a large pan, melt the butter over medium heat. Add the diced onion and bell pepper and cook until softened.

3. Add the button mushrooms and cook for another 5 minutes.

4. Stir in the tomato puree and cook for 2 minutes.

5. Pour in the double cream and bring to a simmer. Cook for 5 minutes, stirring occasionally.

6. Meanwhile, cook the pasta according to package instructions. Drain and set aside.

7. Add the cooked potatoes, carrots, and pasta to the creamy sauce. Stir well to combine.

8. Season with salt, pepper, and any other desired seasonings.

9. Serve hot and enjoy!