1. Make the coleslaw by combining the crème fraîche, mayonnaise and sweet mustard. Season to taste with salt, pepper and sugar. Add the cabbage and carrots and stir until everything is combined. Let stand for about an hour.
2. Preheat the oven to 200°C.
3. Form the ground beef into 4 patties of approx. 125 grams each and season well with salt and pepper. Heat an oven-proof pan over medium-high heat, and drizzle with oil. Cook the patties until browned on each side.
4. Brush the patties with a generous amount of barbecue sauce and place in the oven for 6-8 minutes. Then top with the Castello Burger Blue slices and put back in the oven for a couple of minutes until the cheese has melted.
5. While the burgers are in the oven, lightly toast the buns.
6. Assemble the burgers by placing a spoonful of coleslaw on the bottom half of the bun. Then add a beef patty and a slice of tomato and finish off with the top half of the bun spread with barbecue sauce.