Prepare: Remove the darkest portion of the leeks and the root. Cut in half lengthwise and rinse the layers. Slice crosswise very thinly.
Prepare: Peel and slice the parsnips less than ½ inch thick. Dice the celery and mince the garlic.
Heat the olive oil in a large, heavy bottomed pot over medium heat.
Add the leeks and cook for 7-10 minutes, stirring regularly, until very soft.
Add the parsnip, celery, garlic, thyme, and sage. Stir to evenly distribute everything.
Reduce heat to medium-low and pour in the vegetable broth. Cook for 30-40 minutes until the vegetables are very soft.
Remove from heat and add salt and pepper. Use an immersion blender (or transfer small portions to a regular blender) to puree the soup until it is very smooth. Adjust seasoning to taste. If you don't have a blender you can also use potato masher.
Garnish with chopped chives or green onion to serve.
Notes
To enhance the soup's flavor, roast the parsnips and leeks before adding them to the pot. Toss the chopped vegetables with olive oil, salt, and pepper, and roast in 400°F the oven until they caramelize and turn golden brown. Then, proceed with the recipe as usual.
If you prefer a chunkier texture, you can reserve some of the cooked parsnips and leeks before pureeing the soup. Once the rest of the soup is smooth, add the reserved vegetables back in for added texture.
Cut back on the sodium by reducing the vegetable broth and increasing the water, or use.
If you don't have a blender you can use a potato masher, however, it will not be quit as creamy.
Can be stored in the fridge for up to 3 days and frozen in individual portions for up to 1 month.