Wash the potatoes (no need to peel), then slice into batons just over 1 cm thick. Place them in a large bowl, cover with cold water, and let soak for 1 hour.
Once ready to cook, drain the potatoes and pat dry with paper towels. Toss with vegetable oil, salt, and pepper, then place in Drawer 1 of your Instant Air Fryer.
Drizzle the filet steak with a little oil, season generously with salt and pepper, and place in Drawer 2.
Select Drawer 1, then select Air Fry. Set the temperature to 375°F / 191°C and the time to 25 minutes.
Select Drawer 2, then select Grill. Set the temperature to 400°F / 204°C and the time to 10 minutes (for rare / medium-rare). Press SyncFinish to ensure both drawers finish cooking at the same time.
Once cooking is complete, remove the steak and cover with foil and a tea towel to rest for 10 minutes.
Increase the temperature in Drawer 1 to 400°F / 204°C and Air Fry the fries for an additional 10 minutes until golden and crispy.
While the fries finish cooking, prepare the béarnaise by blending egg yolks, hot sauce, vinegar, and a pinch of salt in a jug or mixing bowl using a stick blender. Slowly drizzle in hot butter while blending until the sauce emulsifies and thickens. Stir in chopped tarragon and season to taste.
When the fries have finished, slice the rested steak into medallions. Plate alongside the crispy fries and fresh arugula, then drizzle the béarnaise sauce over the steak. Enjoy!