Mashed Potato Soup with Wasabi and Chives

Mashed Potato Soup
Morimoto Restaurant

Acclaimed Chef Masaharu Morimoto, perhaps best known as the star of Iron Chef and Iron Chef America, is known throughout the world for his seamless integration of Western and Japanese ingredients and techniques. This Thanksgiving, he has some great tips and recipes for how to utilize your leftover ingredients to create a delicious, next-day dish:

“Use your leftover ingredients and incorporate unique and interesting additions to make the dish seem exciting and new,” says Chef Morimoto.

For his leftover recipe, he recommends Mashed Potato Soup with wasabi and chives. This dish uses the leftover potatoes that you already have for Thanksgiving dinner, and incorporates new, Asian ingredients to keep guests excited about the dish.

4
Servings
352
Calories Per Serving
Deliver Ingredients

Ingredients

For the mashed potatoes

  • 1 large baking potato, such as Idaho or russet
  • 12 Tablespoons unsalted butter
  • 3/4 Cups half-and-half
  • 4 Cups dashi
  • 2 Tablespoons sake
  • 3 Tablespoons light-colored soy sauce
  • salt
  • 1 Ounce caviar, optional
  • freshly grated wasabi and finely sliced chives, preferable baby chives for garnish

For the dashi

  • 1 piece of dashi kombu, 4 x 6 inches
  • 4 Cups filtered spring water
  • 1/2 Cup loosely packed bonito flakes

Directions

For the mashed potatoes

Prick the potato in a couple of places. Steam over boiling water until the potato is tender when pierced with the tip of a sharp knife, 30 to 35 minutes.  Let cool, then peel off the skin. Press the potato through a ricer or a wire sieve set over a medium saucepan, scraping with a rubber spatula to pass it all through.
In a small saucepan, combine the butter and half-and-half.  Warm over medium heat until the butter melts and the liquid is steaming but not simmering.  **Can also use leftover mashed potatoes.

Place the saucepan of mashed potatoes over low heat.  Slowly whisk in the hot butter and half-and-half until the potatoes are thick and smooth.  Remove from the heat and cover to keep warm.

Quickly bring the Dashi, sake, and soy sauce to a boil over high heat.  Spoon equal amounts of the mashed potatoes into 4 soup bowls.  Gently ladle the hot Dashi over and around the potatoes.  Top with a spoonful of caviar if you have it.  Garnish with the grated wasabi and chives.  Serve immediately.

For the dashi

The night before using the dashi, wipe the kombu clean with a wet kitchen towel to remove any grit, but do not rub off the white powder; much of the flavor lies in its natural MSG. 

Place in a medium saucepan and add the spring water.  Let stand at room temperature overnight. The next day, remove the kombu and bring the water to a simmer over medium heat. 

When it reaches a boil, remove from heat and add the bonito flakes.  Let stand until the bonito flakes sink to the bottom of the saucepan, about 15 minutes. Line a wire sieve with moistened, squeezed dry cheesecloth and place over a bowl.  Strain the dashi through the sieve.  Use the dashi within a couple hours of making.

Nutritional Facts

Total Fat
15g
21%
Saturated Fat
2g
8%
Cholesterol
41mg
14%
Carbohydrate, by difference
33g
25%
Protein
18g
39%
Vitamin A, RAE
19µg
3%
Vitamin B-12
1µg
42%
Calcium, Ca
79mg
8%
Choline, total
36mg
8%
Fiber, total dietary
1g
4%
Folate, total
61µg
15%
Iron, Fe
3mg
17%
Magnesium, Mg
42mg
13%
Niacin
3mg
21%
Phosphorus, P
262mg
37%
Selenium, Se
5µg
9%
Sodium, Na
1070mg
71%
Water
224g
8%
Zinc, Zn
1mg
13%

Potato Soup Shopping Tip

Buy fresh herbs and spices to season your soup; fresh garlic, parsley, and thyme will enhance the flavor without being overpowering.

Potato Soup Cooking Tip

Most soups are better the day after their made. If possible refrigerate your soup overnight before serving.