Remove the tough ends from the asparagus by bending the stalks between both hands— they will naturally snap at the desired point. Place the ends in a saucepan and cover with the stock. Bring to a simmer.
Roughly chop the remaining asparagus (don’t be fussy, you will be pureeing it), reserving ¼ cup of the tips for the garnish. Set aside.
Bring a sauté pan up to medium heat and add the butter, allowing it to melt and bubble. Before it browns, add the shallot and garlic. Sauté the aromatics until light brown, this should only take 3-4 minutes. Turn off the heat. (If you are using the optional crispy prosciutto garnish, do not clean the pan, you will use it again.)
Remove the asparagus stems from the stock with a slotted spoon, and discard them, allowing the stock to keep simmering. Add the aromatics from the pan and the chopped asparagus to the stock and simmer until the asparagus turns bright green (about 5 minutes). Turn off the heat.
Using an immersion blender, puree all of the contents of the saucepan (you can do this directly in the saucepan), until smooth. BE CAREFUL WITH THE HOT LIQUID: keep the immersion blender submerged and watch out for sprays. Once the soup is smooth, add the yogurt and the lemon juice. Purée again until all ingredients are incorporated. Taste, and add salt and pepper to your liking (1-2 tsp salt and a few grinds of pepper should do it).
To chill— You will have about 32 oz of soup, depending how much liquid cooked off during your simmer. This fits nicely in a large mason jar, which won’t take up a ton of space in your fridge or freezer. Refrigerate until you are ready to enjoy (within 1 hour or the next day). If you would like to hurry the chill along, portion the soup into your serving bowls and place the bowls with soup in the freezer for 15-20 minutes.
For the prosciutto garnish— While the soup is chilling, turn the heat back on to medium for your sauté pan. Wait for the leftover butter from the aromatics to warm (when you roll the pan side to side, you will see the butter slide quickly). There will not be much butter left and that’s just fine because the meat will render it’s own oil to brown, the butter just helps keep it from sticking. Place 3-4 prosciutto slices flat in the pan, browning until the bottom is crispy, then turning (2-3 minutes). Once both sides are crispy, place the slices on a paper towel to absorb excess oil. (NOTE: prosciutto is quite salty, so go easy on the sea salt garnish if you are also adding the prosciutto.)
To garnish— Chop the radishes into a small dice (1 per person). Center the radishes and asparagus tips in the middle of the soup, and sprinkle the chevre (optional), prosciutto (optional), sea salt, and pepper over the top.
This soup will come together so quickly, you will be giving yourself pats on the back all night for creating something incredibly seasonal, delicious and healthy in 20 minutes! Not to mention it’s a beauty on your table in green and pink. It is also a handy template for capitalizing on any of your favorite springtime greens. Peas would work splendidly here, as would a combination of lettuces (yes, lettuce soup!). You could use arugula, watercress, and romaine to really clear out your produce drawer. Though the yogurt is a delicious, tangy addition to the soup, it can easily be made vegan by going without. No substitution is needed, the texture just won’t be as thick. However, if you’d like to really amp up the protein, add the prosciutto garnish and some grated, hard-boiled egg.
Not only is asparagus high in fiber, folate and several letters of the alphabet, including fat soluble vitamins A,C, E, and K, but it’s got a little something special going on in the form of chromium. Chromium is a trace mineral that helps regulate blood sugar by supporting the insulin transportation of glucose from the bloodstream into cells where it can be metabolized. This means that your body can actually use the ‘sugar’ fuel that you are feeding it instead of sending it straight to an overworked liver.