1. Melt the butter in a saucepan over medium heat.
2. Add the flour and mix well until a roux forms. Cook for 1 to 2 minutes, stirring constantly.
3. Gradually add the milk, stirring to avoid lumps. Allow to thicken slightly.
4. Add the crème fraîche and mix until a homogeneous mixture is obtained.
5. Reduce heat to low and add the shredded cheddar cheese gradually, stirring until completely melted.
6. Season with salt, pepper and paprika if using. Mix well.
7. Serve immediately with hot chips or other snacks.
