Start by heating oil in a stainless steel skillet on high heat. Add rice and butternut squash, stirring until it becomes fragrant and rice is almost translucent.
Once all grains and squash are well coated in oil, add 1 cup vegetable stock and stir. Once the mixture becomes dry again, add more stock and stir. Drop the heat to low, add the rest of the stock, and allow the rice and squash to steam cook the rest of the way, stirring occasionally. When the rice and squash are fully cooked, add corn.
For the wojape, start by heating blueberries, lemon juice, and pepper in a saucepan on medium-high heat. Cook for about an hour, then pour into a blender while still hot. Blend on high till the sauce is smooth and thick.
For the cod, cut the loin into 4 even portions. Cut the bread to match the outer surface of each portion of cod and wrap tightly with plastic wrap to create 4 parcels. Set dashi to a simmer, then poach all of the parcels in the simmering dashi for 2 minutes. Remove and let cool.
While dashi is still simmering, poach quail eggs and set aside. Once the parcels are cooled, carefully unwrap them and place on a wire rack. Heat butter in a skillet. Once the butter is frothy, add cod bread side down and toast until golden brown. Arrange all cooked components on a plate or bowl however you like, then serve.