Steamed buns are one of my all-time favorite foods because of how soft and sweet they are. These are inspired by some delicious steak buns that I had in Hong Kong a long time ago. They came with an amazing peanut sauce for dunking and I still dream about them.
For the meat and marinade: Combine the sambal, honey, curry powder, salt, black pepper, garlic and approximately two-thirds of the coconut milk (make sure you SHAKE WELL before opening the can) in a bowl and whisk together (reserve the remaining coconut milk for the peanut sauce). Submerge the flank steak in the marinade, cover and refrigerate for at least 2 hours and up to overnight.
For the bun dough: In the bowl of a stand mixer fitted with a dough hook, combine the all-purpose flour, cake flour, sugar, yeast and salt and whisk to combine. Add the water and shortening and mix for 10 minutes. Transfer to an oiled bowl and let sit until doubled in size, 1 to 2 hours.
Cut eight 3-inch squares of parchment paper. Divide the dough into 8 pieces. Roll each piece into a flat oval, about 6 inches by 3 inches. Brush with sesame oil, fold in half and place on a parchment square. Set the buns in a bamboo steamer 1 inch apart, cover and allow the buns to proof in the steamer in a warm place (or just on the countertop), until doubled in size, 30 to 40 minutes.
For the peanut sauce: Meanwhile, combine the reserved coconut milk, peanut butter, sambal, jalapeno and soy sauce and whisk until smooth. If the sauce is too thick, add a splash of water. Reserve at room temperature until serving. (If you make it ahead of time, refrigerate the sauce but take out in time for it to come to room temperature before serving, or it will be very thick.)
Heat a grill or grill pan to medium-high heat.
Remove the meat from the marinade and brush off any excess. When the grill is very hot, grill the meat to desired doneness, 4 to 8 minutes on each side is good for medium rare, depending on thickness. Let rest for at least 10 minutes so the juices can settle.
Bring a large pot of water to a boil. Steam the buns over the boiling water until puffy and cooked through, 10 to 12 minutes.
Slice the meat thinly against the grain. Serve the buns right out of the steamer with the sliced meat, peanut sauce, pickles, extra sambal, cilantro and salt to taste.