Pumpkin Curry with Citrus Notes

1/2 large yam or 1 sweet potato

1 to 1 1/2 cups cherry tomatoes

1 cup chickpeas

2 tablespoons freshly grated orange zest

Curry Sauce

1 shallot

4 cloves garlic, sliced

1 to 2 red chilies or 1 to 2 teaspoons chili sauce

1 can coconut milk

1 teaspoon tamarind paste

3 tablespoons soy sauce

2 teaspoons brown sugar

juice of 1/2 lime

juice of 1 orange

1/2 teaspoon turmeric

1 tablespoon rice vinegar

1 tablespoon coriander seeds , ground

1 tablespoon cumin seeds , ground

1 teaspoon fennel seeds , ground