Warm a skillet over medium heat and add 2 tsp unsalted butter. Once melted, add ½ onion (finely diced) and sauté until golden and translucent. Transfer to a wide bowl to cool completely.

Measure 4 tbsp panko breadcrumbs into a small bowl and add 3 tbsp whole milk. Mix to rehydrate the breadcrumbs and make a 'panade'.

Take a large bowl and add 200 g ground beef, 100 g ground pork and ½ tsp salt. Knead for about 1 minute to evenly distribute, being careful not to overwork it.

Add the panade, ¼ tsp ground black pepper, and 1 pinch nutmeg powder to the bowl. If you used lean meat, consider adding ½ tbsp lard to make the patties juicer. Mix with open fingers until evenly distributed.

Gently knead, then divide into 2 equal pieces for large adult portions, or 3 for standard portions or 4 for small portions.

Toss each ball from one hand to the other to remove air pockets, the motion through the air keeps the meat cool. Shape into ovals about 2cm thick and make a shallow dent in the center on one side. Rub your finger along any cracks to smooth them out.

Place the shaped patties in a wide sealable container, then cover and refrigerate for 20-30 minutes.

Heat a skillet over medium and add ½ tbsp cooking oil. Once hot, place the patties in the pan with the dimple-side facing up and sear for about 2 ½ minutes or until the underneath has formed a thin brown crust.

Flip and fry on the other side for 1 ½ minutes.

Splash 1 tbsp water into the pan and cover with a lid. Steam for 3 minutes, then turn off the heat and leave covered for 1 minute to continue gently cooking in the residual heat.

Check the internal temperature of the patties with an instant-read thermometer. They should read 71-75℃ (160-167°F) or the juices should run clear. Transfer to a wire rack to rest for 1-2 minutes.

While you wait, return the pan to a low heat and deglaze by adding 1 tbsp red wine and scraping the bottom of the pan with a spatula.

Add 2½ tbsp tomato ketchup, 1 tbsp Worcestershire sauce, ½ tbsp honey, ½ tsp smooth Dijon mustard, ½ tsp Japanese soy sauce (koikuchi shoyu), and ⅛ tsp dashi granules to the pan and mix until combined. Simmer for about 1 ½ minutes or until slightly thickened and syrup-like. Finish with 1 tsp unsalted butter and mix until melted into the sauce.

Place the patties on serving plates along with your choice of sides. I opt for cooked Japanese white rice, steamed vegetables and a sunny-side fried egg. Drizzle with the sauce and enjoy!