Keeper Project: Okinawan Sweet Potato Bars with Haupia

I am not precise. My bottom dough is always lumpy and uneven. This is a difficult recipe in that it takes a lot of steps. Still, this is a keeper recipe because it always tastes yummy, unless you are Boy 1 who does not like coconut and coconut products. Whose child is this anyway?

First, another must have tool. This potato ricer is a difficult tool for me. I put too much in it and then I need Big Spazz to use his kung fu grip to push the sweet potato through the ricer. However, the texture of the sweet potato from the ricer is fluffy and light. It's the perfect texture for these bars.

Ingredients:

Press-In Shortbread Crust:

• 2 Tbsp sugar
• 1-1/2 cups flour
• 1-1/2 sticks cold butter (12 Tbsp, 3/4 cup)
• (optional) 1/2 cups chopped toasted Macadamia nuts

Okinawan Sweet Potato Filling:

• 1 stick room temperature butter (8 Tbsp, 1/2 cup)
• 1 cup sugar
• 2 eggs, beaten
• 2 generous cups Okinawan sweet potato
• 1/2 cup evaporated milk
• 1 tsp vanilla
• 1/4 tsp salt

Haupia Topping (Coconut Pudding):

• 2/5 cup sugar (about 6-1/2 Tbsp)
• 2/5 cup cornstarch (about 6-1/2 Tbsp)
• 1-1/8 cup water (1 cup + 2 Tbsp)
• 1 can (19 oz) coconut milk (preferably Mae Ploy brand since it is very creamy)
• 1/4 tsp salt

Directions:

Press-In Shortbread Crust:

Preheat the oven to 325 F. Butter or lightly oil a rectangular-shaped or square-shaped baking pan. Combine the sugar and flour. Cut or use your fingers to rub the butter into the flour mixture until sandy. If the butter starts to melt or becomes too soft, place it in the refrigerator or freezer for a few minutes to cool and then continue. (I always have to do this, one because we live in Hawaii and two because my hands are always too hot for the dough and my butter keeps melting). 

Press the crust mixture lightly into the bottom baking pan as evenly as possible.  Freeze the crust for at least 30 minutes to firm it before baking. The unbaked crust can be made ahead of time and stored frozen. 

Bake at 325 F for 20 – 25 minutes, or until the crust is pale but very lightly browned. Let cool.

Okinawan Sweet Potato Filling:

Preheat the oven to 350 F.

You can cook the Okinawan sweet potatoes by baking, boiling, or steaming them. I suggest steaming them whole, since this best preserves their color and moisture, however, when I boil it I find that it cooks more evenly.

To steam the Okinawan sweet potatoes whole: Fill the bottom of a large pot with a tight-fitting lid with a few inches of water (the water level should be below the shelf of your steaming rack or metal colander so that the Okinawan sweet potatoes don’t get wet). Heat on high until boiling. Reduce heat to medium. Place a metal steaming rack or metal colander in the pot. Place the Okinawan sweet potatoes on the rack, cover with a tight-fitting lid, and steam until they can easily be pierced with a fork (about 30 minutes). They should be steamed over gentle heat; reduce the heat if the top of the pot is clanking a lot due to releasing steam.

When the Okinawan sweet potatoes are cool enough to handle, peel them and then mash them with the potato ricer. 

Beat the butter and sugar. Mix in the eggs. Gradually mix in 2 cups of mashed Okinawan sweet potatoes. Add the evaporated milk, vanilla, and salt. Slowly increase the mixing level to medium-high and whip the mixture as you would to make whipped potatoes (e.g. to level 8 out of 10) in order to incorporate air into the filling.

Pour the filling into the crust. Bake at 350 F for 30 to 35 minutes, or until a toothpick comes out mostly clean but has a few moist crumbs stuck to it or some moisture on it (this indicates that the filling is cooked through but is still moist). Cool.

Haupia Topping (Coconut Pudding):

Mix sugar, salt, and cornstarch in a medium pot. Stir in water and blend well. Add the coconut milk. Cook over medium-low heat, stirring constantly, until the mixture thickens, but doesn’t boil. It will become very thick, similar to a frosting.

Cool slightly, and then pour the haupia over the pie filling, until it covers the pie and nearly fills the crust Use a spatula to smooth the top of the haupia topping.

Refrigerate; the haupia will become solid, similar in texture to Jello and other gelatin desserts.