In a medium pan or shallow pot, turn the heat to medium and add butter.
When the butter start melting, add sliced onion. Cook until the onion gets a little bit softer.
Add uncooked rice to the pan and cook on high heat for 30 seconds. After 30 seconds, turn the heat to medium.
Add cooked bacon and smashed kabocha in the pan.
Add water, salt, and black pepper and bring to boil. After boiling, cook for 10 minutes.
After 10 minutes, add milk and simmer for 15 minutes.