Cut any smaller mushrooms into halves or quarters and cut any larger ones into bite-sized pieces.
Heat the oil and butter in the insert pan of a slow cooker or a large frying pan over medium heat. Cook the shallots, garlic and paprika for 2 minutes. Add the mushrooms and cook for 3–4 minutes until starting to soften. Add the flour and cook for 2 minutes.
Return the insert pan, i