Prebiotic-rich Potato Leek Tart (Grain-free)
Ever wonder what to do with a leek? They are a favorite vegetable in my household for their delicate, sweet onion flavor that sweetens as its cooked. They can be found in most groceries and look like extremely large green onions. Like other members of the onion (allium) family, leeks have a number of benefits including vitamins and minerals, phytonutrients and an important type of gut-healthy, prebiotic fiber.
What is a prebiotic verse a probiotic?
The digestive tract is home to more than 500 species of bacteria. The average gut may contain about 100 trillion bacteria which rivals the number of human cells that make up our body. Collectively this mass of bacteria is called the microbiome. It is tremendously important for overall health. Our gut gives the microbiome a home and in exchange, it does a variety of things for us. The beneficial bacteria in our gut help digest food, synthesize certain vitamins, and play an important role in our immune defense. The microbiome also acts as a barrier to help our bodies filter and appropriately absorb nutrients from what we eat.
The ‘good’ bacteria in our gut providing the benefits listed above are often termed probiotics. These bacteria can be constantly replenished by eating fermented foods or taking targeted supplements. In order to thrive however, probiotics also need nourishing food. Prebiotics are fiber-rich foods that probiotics feed and grow on. As an added bonus, a compound called butyric acid is produced when the probiotic bacteria break down prebiotic foods in the colon. Butyric acid is the preferred form of fuel for the cells that line the colon and serves to acidify the gut environment, making it harder for harmful bacteria to survive.
Inulin is a type of prebiotic fiber. Leeks contain up to 16% inulin fiber making leeks a delicious, whole-food, prebiotic powerhouse. Inulin has been shown to reduce gut discomfort, help with constipation and increase the amounts of beneficial Bifidobacteria and Lactobacilli bacteria in the gut. Other rich sources of prebiotic fiber include asparagus, banana (the greener the better), dandelion greens, eggplant, endive, garlic, honey, Jerusalem artichokes (sunchokes), jicama, kefir, legumes, onions, peas, radicchio, whole grains, and yogurt. Start with small portions when newly incorporating these foods in your diet. Aim for a serving or two of prebiotic-rich foods daily to help promote a thriving microbiome. The fiber will encourage growth of good bacteria in your gut, but too much too quickly can cause discomfort.
Potato Leek Tart
This tart is a frequent request at my house in the fall when leeks are in season. It is inspired by the tradition of beautiful, French, vegetable tarts. In the summer, I substitute squash and caramelized onions for the potatoes and leeks. This is one of my daughter’s favorite meals and her birthday meal request.
Author: Erica Leazenby, MD
TIme: 75 minutes
Serves: 6
Ingredients:
For the crust:
2 cups almond flour
1/2 cup arrowroot flour
1/4 teaspoon sea salt
1/4 cup coconut oil, solid
2 Tablespoons unsweetened nut milk
1 egg, beaten
For the filling:
2 Tablespoon olive oil
2-3 leeks, white and light green parts only, cleaned* and chopped into semi-circles, about 2 cups
2 large organic Yukon gold potatoes, about 1 lb, diced into 1 cm cubes (I leave the skin on for extra fiber.)
1 Tablespoon Dijon mustard or enough to lightly coat the bottom of the crust
1/2 tsp salt and more to taste
Pepper to taste
Directions:
Preheat the oven to 350 degrees or 325 degrees if using a convection oven.
Prepare a 10-inch tart pan by lining the bottom with parchment paper and greasing the sides and bottom. Set aside. You can also use a pie pan or baking dish if you do not have a tart pan.
Make the crust: Combine the almond flour, arrowroot flour and salt in a mixing bowl and stir until well mixed. Using a pastry blender or fork, incorporate the oil into the dry ingredients. Once the oil is evenly incorporated and the dry mixture is the consistency of sand, make a small well in the dry ingredients. Add the nut milk and egg to this well. Slowly stir the wet ingredients in the well while incorporating the dry ingredients until a dough forms. Use clean hands to form the dough into a disk. The dough can be rolled immediately. If it is sticky or warm, wrap the dough well in plastic wrap or a reusable silicone bag and refrigerate for 30 minutes.
Roll the dough on parchment paper until it is about 1/4 inch thick. Using the parchment paper, gently transfer the rolled dough to the tart pan. Use your fingers to piece the dough back together if it breaks apart.
Using a fork, prick the dough several times around the bottom of the pan. Bake the tart without ingredients (blind) for 20-25 minute or until the dough is just starting to lightly brown.
While the tart is baking, prepare the filling: Heat the olive oil in a large pan over medium heat. Add the prepared leeks and sauté until they start to soften. Add 1/2 tsp of salt and the potatoes to the leeks. Sauté the potatoes until soft, but still holding their shape. Taste the mixture and add salt and pepper as needed.
Once the blind tart is lightly browned, pull it from the oven. Gently coat the bottom of the tart with a thin layer of Dijon mustard. Place the potato leek mixture in the tart and return the pan to the oven. Bake for an additional 20-30 minutes or until the tart crust is nicely browned.
Serve immediately
*Leeks are often full of dirt and silt. I recommend soaking and swirling the cut leeks in a bowl of water briefly in order to remove all the impurities.
This tart is delicious hot or cold. I like to serve it with a simple butter leaf salad or a bowl of soup. Sometimes I will add a can of white beans to the potato mixture to make the tart a more hardy main course option. We avoid dairy, but Parmesan, goat or feta cheese would be an excellent garnish if you are dairy tolerant.
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