Method

1. Start by removing steaks from fridge to come to room temp and preheating a very low oven at 170–200°F.
2. Thinly slice the cucumbers with a knife or mandolin then place them in a large bowl and sprinkle generously with 1–2 tbsp salt. Let sit for 10 minutes.
3. Place cucumbers in a colander and rinse very well under cold water to remove the salt. Squeeze cucumbers well with your hands to remove excess water and drain.
4. Make the dressing by whisking together rice vinegar, white sugar, soy sauce, sesame oil and a pinch of salt. Add cucumbers and toss to coat.
5. Add sesame seeds, toss again and transfer to a serving bowl. Set aside in the fridge until ready to serve.
6. Slice the onions into ½-inch thick slices and peel off the outer skin. Separate onions into rings then peel the inner membrane off each ring.
7. Set a large Dutch oven half filled with vegetable oil with a thermometer over high heat and bring temp up to 350°F, maintaining this heat throughout.
8. Place a wire rack on top of a sheet tray and set beside the Dutch oven.
9. Make the batter by adding rice flour, baking soda and baking powder to a large bowl and whisk to combine.
10. Make a well in the center of the flour, separate an egg and place just the yolk in the center. Break up the yolk with a fork.
11. Slowly add the beer to the well, whisking as you add, bringing the dry mixture into the beer. Continue whisking until batter is smooth. If batter looks too dry add a splash or two of beer.
12. Place dredging rice flour in a bowl, add onion rings and toss to coat.
13. Pull flour-coated onion rings from dredge and place into batter in batches, tossing gently to coat, then place straight into the hot oil to fry.
14. Fry in batches until golden brown, about 3 minutes per batch. Remove each batch to the wire rack and sprinkle with salt.
15. When all are fried, place in the very low oven to hold warm.
16. Set a large cast iron skillet over medium high heat and allow to heat up 3–5 minutes until very hot. Add a tiny amount of grapeseed oil then add the steaks.
17. Sear on one side 2–3 minutes without touching to form a good crust. Flip and sear another 2–3 minutes.
18. Turn heat to low, add butter and garlic to the pan, and baste butter over steaks quickly with a spoon.
19. Check temp with a meat thermometer for 120–125°F. Keep heat on low and continue basting until steaks reach 120–125°F.
20. Remove steaks to a plate and allow to rest at least 10 minutes.
21. To make the wasabi cowboy butter, add softened butter, parsley, chives, wasabi, horseradish, soy sauce, grated garlic, lemon zest and a generous pinch of flaky salt to a small saucepan.
22. Warm over medium-low heat until only just melted together and whisk to combine. Take off heat immediately and pour into a small serving jug. Set aside at room temperature.
23. To build sandwiches, slice the baguette into 3 even portions and down the side, not cutting all the way through. Place 3 slices of provolone on each baguette and remove onion rings from warm oven.
24. Slice steaks into ½-inch thick slices and layer on top of cheese.
25. Pour wasabi cowboy butter generously over steak slices, top with chives, then add onion rings. Close baguette and serve with cucumber salad on the side.