1. Preheat the oven to 350⁰F.
2. In a pan, melt the butter. Place the whole pork fillet and brown all sides for 2 minutes.
3. Remove the meat and transfer it to a baking sheet. Bake for 20 minutes.
4. Add a little water to the pan to loosen the juices.
5. Add the blueberries to the pan. Reduce heat to low. Pour in the rest of the sugar and red wine. Let it reduce by half. Cover the pot.
6. Slice the pork fillet into thick slices. Serve the pork with the blueberry sauce.