Oyaki (Japanese Stuffed Dumplings)

Name: Oyaki (Japanese Stuffed Dumplings)
Prep time: 1 h 10 min
Cook time: 45 min
Total time: 1 h 55 min
Cuisine: Japanese
Ingredients: 2 ½ cups all-purpose flour (plain flour) ((300 g)); 1 scant cup boiling water ((200 ml)); 1 tsp neutral-flavored oil (vegetable, canola, etc); ¼ tsp kosher/sea salt (I use Diamond Crystal; Use half for table salt); 2 Japanese/Chinese eggplant; 1 Tbsp sesame oil (roasted); 1 Tbsp miso; 1 Tbsp sugar ((you can reduce if you like; See Notes)); 2 Shiso leaves (Ooba) ((optional)); ¼ kabocha (squash/pumpkin) ((11-12 oz or 300-350 g with seeds)); 1 Tbsp neutral-flavored oil (vegetable, canola, etc); ¼ cup water; 1 Tbsp sugar ((you can reduce if you like; See Notes)); 1 tsp soy sauce; pinch kosher/sea salt (I use Diamond Crystal; Use half for table salt); 1 Tbsp neutral-flavored oil (vegetable, canola, etc) ((for cooking oyaki))