Vegan Potato and Butternut Squash Curry

2 tablespoons oil

or as needed

1 onion

chopped

1 teaspoon Madras curry powder

or to taste

1 chile pepper

seeded and chopped

or to taste

1 (14 ounce) can coconut milk

1 butternut squash

peeled and cubed

6 small (3 ounce) potatoes

scrubbed and halved

or to taste

1 ½ teaspoons ground cumin

1 ½ teaspoons ground coriander

¼ teaspoon ground turmeric

⅛ teaspoon cayenne pepper

⅛ teaspoon ground cinnamon

salt and ground black pepper to taste