Step 1

Preheat oven to 325°. Line a 9x5” loaf pan with a double layer of foil, leaving at least 3” overhang on the long sides, and lightly coat with vegetable oil. Whisk eggs, apple, scallions, garlic, ginger, gochugaru, brown sugar, soy sauce, salt, and sesame oil in a large bowl to combine. Add panko and mix with a stiff rubber spatula until well combined. Let mixture sit 5 minutes to hydrate.

Step 2

Stir one-quarter of beef into panko mixture, smashing and folding to combine evenly. Stirring with rubber spatula or using your hands, mix in remaining beef until evenly combined. Transfer to prepared pan and press evenly into pan, working into corners.

Step 3

Bake meatloaf until an instant-read thermometer inserted into the center registers 160°, 1¼–1½ hours. Let cool in pan at least 20 minutes

Step 4

Using foil overhang, remove meatloaf from pan and transfer to a cutting board. Cut meatloaf into 8 thick slices. Heat 1 Tbsp. oil in a large nonstick skillet over medium heat. Working in batches and adding remaining 1 Tbsp. oil halfway through, cook slices, reducing heat if browning too quickly, until deeply browned and warmed through, about 4 minutes per side.

Step 5

Spread gochujang over one side of bread slices and top 8 slices with meatloaf and some kimchi; close up sandwiches.

Step 6

Do ahead: Meatloaf can be baked 4 days head. Let cool; cover and chill.