Makes 5-6 servings.
- 1 large red-skinned sweet potato (yam; no more than 350g)
- 200g sugar, divided
- 2 tablespoons water
- 250 ml half and half
- 4 large eggs
- 125 ml whipping cream
- 1/4 teaspoon salt
- 2 tablespoons tawny Port (tawny, not ruby red – the color is important!)
Prepare the potato pure in the oven:
- Preheat oven to 350°F.
- Pierce sweet potato with fork
- Roast until tender, 1 to 1 1/2 hours, depending on width of potato.
Or prepare it in the microwave:
- Place a potato in on High for about 3 minutes
- Let sit 3 minutes;
- Start again for 3 minutes;
- Let sit for 3 minutes
Make a puree
- Cool sweet potato
- Cut potato in half and scoop flesh into mini processor; puree until smooth. This may be done in a blender, or by hand… depending on your preference. I find the hand held single blade rotary things most effective.
- Measure 250g puree (reserve any remaining puree for another use).
Prepare the caramel:
- Stir 100g sugar and 2 tablespoons water in medium saucepan over medium-low heat until sugar dissolves.
- Increase heat to high and boil without stirring until syrup turns deep amber, occasionally swirling pan and brushing down sides with wet pastry brush, about 5 minutes.
- Immediately pour caramel into 20 cm -diameter metal cake pan, leaving about 2 tablespoons caramel in saucepan.
- Using pot holders, swirl cake pan, allowing caramel to coat bottom and about 1/2 inch up sides.
Prepare the filling
- Preheat oven to 350°F
- Add half and half to remaining caramel in saucepan.
- Stir over medium-low heat until caramel dissolves.
- Whisk eggs in medium bowl until frothy.
- Whisk in cream, salt, sweet potato puree, and remaining 100g sugar.
- Gradually whisk in hot half and half mixture.
- Strain into same saucepan.
- Stir over medium heat 1 minute.
- Remove from heat; whisk in Port.
- Pour custard into prepared cake pan.
Bake the whole thing
- Place cake pan in large roasting pan.
- Add enough hot water to roasting pan to come halfway up sides of cake pan.
- Bake until just set in center, about 1 hour.
- Remove flan from water.
- Chill until cold, about 5 hours.
- Dip bottom and 1 inch up sides of cake pan into pan of hot water 15 seconds.
- Wipe dry.
- Invert onto rimmed plate, scraping caramel in pan over flan