How to Make It
In a small saucepan, heat 3/4 cup of grapeseed oil until shimmering. Add the garlic and cook over moderate heat, stirring, until golden and crisp, about 8 minutes. Using a slotted spoon, transfer the crispy garlic to paper towels to drain. Let the oil cool.
Using a small paring knife, make 5 slits in each steak. Press 1 crispy garlic chip into each slit. In a large resealable plastic bag, mix the cooled garlic oil with the shallots, lime leaves, orange zest, soy sauce, fish sauce, chiles, 8 of the thyme sprigs and the rosemary leaves. Add the steaks, seal the bag and turn to coat. Marinate in the refrigerator for 4 to 8 hours, turning occasionally.
Remove the steaks from the bag and scrape off the marinade. Season the steaks with salt and black pepper and let stand at room temperature for 30 minutes.
Meanwhile, in a large saucepan, melt the remaining 2 tablespoons of butter over moderately high heat. Add the kale and cook, tossing, until just wilted, about 1 minute. Remove from the heat and stir in the mustard greens until they just start to wilt. Season with salt and white pepper. Drain the greens in a colander and mound on the plates. Serve right away with the sour cherry mustard.
Make the Sour Cherry Mustard.