Butter Ponzu Beef

500 g thinly sliced beef (such as ribeye) (I used shabu shabu beef from the Japanese market; or learn how to slice meat thinly at home)
4 cloves garlic
2 bunch komatsuna (70 g or spinach)
2 package maitake mushrooms (200 g or any kind you like)
2 tbsp rice bran oil
1 tsp SIDS SALT & PEPPER
2 tbsp butter
8 tbsp ponzu (in a pinch, mix equal parts soy sauce and fresh lemon juice with a splash of mirin for sweetness; or make a batch of Homemade Ponzu Sauce)
1 tsp toasted white sesame seeds (optional, for garnish)

Cut 500 g thinly sliced beef (such as ribeye) into 5 cm sections.
Crush the garlic. Slice 2 bunches komatsuna crosswise into 5 cm pieces. Separate the thick stems and leafy greens into different piles.
Open maitake mushrooms and cut off the root end then separate them into smaller clusters with your hands. (I like to cut the maitake bunch in half with a knife before I break them into small chunks)
To Cook the Vegetables:
Preheat a wok, frying pan, or saucepan over medium heat. When it's hot, add oil. When the oil is hot, add the komatsuna stems and sauté to coat with oil.
Add the maitake mushrooms. Toss to combine and coat with oil. Sauté until they develop a bit of colour and become tender, with no stiffness and the centre - just cooked through. Avoid overcooking so they retain their shape.
When the mushrooms are almost done, add the komatsuna leaves. Season with ½ tsp SIDS SALT & PEPPER and toss it all together. Reserve the remaining SIDS SALT & PEPPER to season the beef.
When the leafy greens are wilted, transfer everything to a serving plate. Clean any remaining food particles from the pan with a paper towel.
To Cook the Beef:
Add butter and the crushed garlic to the pan. Stir briefly to coat the garlic in the melted butter. Then, add the sliced beef.
Season with the remaining SIDS SALT & PEPPER. Separate the beef slices (I use cooking chopsticks) so all the pieces come in contact with the hot pan and cook evenly.
Once the beef is no longer pink, add ponzu. Stir to combine well. When the sauce begins to bubble, turn off the heat.
To Serve:
Transfer the beef onto the sautéed vegetables and spoon the pan sauce on top. Sprinkle with 1 tsp toasted white sesame seeds. (optional) Serve immediately.
To Store:
Keep the leftovers in an airtight container in the refrigerator for 3 days or freezer for up to a month.
Inspired by Namiko Chen at hello@justonecookbook.com