In a large bowl, whisk together the flour, sugar, baking powder, ground cardamom (if using), and salt.
In a separate bowl, mix the coconut milk, water, and beaten egg until well combined.
Gradually add the wet ingredients to the dry ingredients, mixing until a soft dough forms.
Knead the dough on a lightly floured surface for about 5 minutes, or until smooth and elastic.
Cover the dough with a damp cloth and let it rest for about 30 minutes.
Divide the dough into small balls and roll each ball into a flat circle, about 1/4 inch (0.6 cm) thick.
Cut each circle into quarters or desired shapes.
Heat the vegetable oil in a large, deep skillet or pot over medium heat until it reaches 350°F (175°C).
Carefully place a few pieces of dough into the hot oil and fry until golden brown on both sides, about 2-3 minutes per side.
Use a slotted spoon to remove the fried mandazi from the oil and place them on a paper towel to drain excess oil.
Dust the mandazi with powdered sugar if desired.
Enjoy your meal!