Place kabocha squash on an aluminum lined baking tray. Sprinkle salt and pepper over squash. Drizzle with olive oil. Roast in oven for about 45 minutes until tender.
Rinse and drain kale. Remove center stem and cut leaves into 3 inch lengths. About 10 minutes before squash is done, place kale in a steamer and steam for 30 seconds. Remove and drain.
Divide squash and kale onto 2 salad plates.
Combine miso with sugar and ¼ cup (60ml) water in a small saucepan over low heat. Whisk to melt miso and sugar. Turn off stove but leave saucepan on heating element. Add butter and continue to whisk until a smooth sauce forms. Pour over squash and kale.
Sprinkle with toasted pumpkin seeds and serve immediately.