Photograph: Dan Jones
Preheat the oven to 220°C, fan 200°C, gas 7. Pick out 25 evenly shaped potato cubes and place on a baking sheet. Bake for about 25 minutes until crisp and golden.
Meanwhile, preheat a griddle pan. Season the steak, rub with oil and griddle for 2-3 minutes on each side until medium done, or to your liking. Leave to rest for 15 minutes.
Trim the fat off the steak and cut it into 1.5-2cm cubes. Skewer a cube of steak and potato on to each cocktail stick. Serve with the béarnaise sauce for dipping.