French onion lentil and spinach soup

This soup is healthy, warming, comforting, and filled with iron and fiber. It also tastes better the second day, so double the batch and enjoy the leftovers all week!

Take me to the recipe!

I started making this soup when I was pregnant with Z and the thought of eating meat really turned my stomach. I was looking for nourishing soups that also tasted great and kept me full because while I LOOOOOOVE a soup, they don’t always fill me up unless they’re cream-based or more of a stew.

Enter this soup. It starts off with a base of caramelized onions like you’re making French onion soup. I use a super-quick method for caramelizing onions that might take a minute to get the hang of, but turns raw onions into melty, caramelized goodness in about 20-25 minutes instead of 45-60 minutes. I outline the process here.

Basically, you’re using high heat and a covered pan while also de-glazing every 2-3 minutes to achieve that deep, rich color and flavor by utilizing all of the stuck on bits at the bottom of the pan. It can be tricky to find that sweet spot between browning and burning, but luckily, the onions are pretty forgiving and if they get a little too dark, you can just deglaze with a bit of extra water and turn the heat down a smidge.

Once you have those jammy onions in the bag, you can basically add the rest of the ingredients (with a little watching for a few minutes) and let the stove do the rest of the work.

This soup makes me so so happy. I’ve made it for new moms during those rough postpartum days. I’ve also made it for snow days and arctic days, regular days and special days. I always wish I was eating it in front of a fire wearing a huge sweater and reading a book, but alas, that never happens.

French onion lentil and spinach soup

5 cups sliced onions (about 3 large onions, sliced 1/8th of an inch thick)
3 Tbsp butter or olive oil (or a combo)
2 cups water
½ tsp dried thyme or 2 sprigs fresh thyme
1 tsp kosher salt 
1 Tbsp red wine vinegar
4 cups beef broth 
¾ cup dried green or brown lentils
1 cup frozen spinach or 1 bag fresh baby spinach 

Time: About 1 hour (30 minutes active)
Yield: about 5 cups of soup

 Slice the onions into 1/8th to 1/4th inch slices. 

Heat the oil and butter over a medium flame in a large skillet with high sides. 

Turn the heat up to medium high and add the onions. Cover and cook, for 2-3 minutes until the onions begin to brown and stick to the bottom of the pan. Pour in about 2 -4 Tbsp of water and scrape the brown bits from the bottom of the pan. Cover and cook for 2-3 more minutes and repeat the process. Continue cooking until the onions are a deep brown color, about 20-25 minutes. 

Add the thyme and salt and cook for 1 minute. 

Add the red wine vinegar and cook until evaporated, about 1-2 minutes.

Add the broth and the lentils. Bring to a boil over the highest flame. Once boiling, reduce the flame to low and simmer, covered, for about 30 minutes until the lentils are cooked, but have a little bit of crunch left to them. (Continue to cook for another 10 minutes if you prefer mushier lentils.)

Turn off the flame and stir in the spinach, either frozen or fresh, and stir to wilt. 

Test for seasoning. 

French onion steak skillet

Valentine’s Day is on the horizon, folks. This is a holiday that I don’t particularly enjoy. If you’re not in a relationship or in one that’s complicated, it can feel like a giant middle finger. If you are in a relationship, it can be stressful and/or tedious to have a mandated celebration of your love. AND EXPENSIVE, AMIRIGHT? There’s definitely surge pricing for restaurants and babysitters. Bleh. I hate it.

So instead, we’ll put the kiddo to bed early, open a bottle of wine, and make this easy French Onion Steak Skillet that requires VERY little work and even less cleanup.

But even on non-holiday nights, if your kids like French Onion Soup or steak, they’ll dig in. No need to save this for a special, adults-only meal.

Also, I think I’ve finally cracked the code for getting GENUINELY caramelized onions (not fried, frizzled, or straight-up burned) in about 20 minutes. I know, I know. Most recipes claim that it takes 20 minutes when it actually takes an hour or more to get that deep uniform jammy brownness. Behold this before and after:

After a deep dive through Youtube videos and Cook’s Illustrated articles, I’ve achieved great results much faster than usual. Here are a few secrets to speeding up this otherwise slow process:

1. Use a large pan with a tight fitting lid. You’ll melt butter and olive oil together and then cook the onions for 3 minutes at a time with the pan covered.

2. Use medium high heat the whole time. You want the onions to brown and stick to the bottom of the pan just a little bit. If they stick too much and/or blacken rather than brown, turn the heat down slightly. If the onions aren’t sticking to the bottom, turn the heat up.

3. Add water or stock every 3 minutes and scrape the browned bits off of the bottom and mix them into the onions while they’re cooking.

4. Repeat the process: Cook 3 minutes over high heat/ add liquid/ scrape the browned bits/ cover and cook for 3 more minutes. After about 15-20 minutes, the onions will be done!

5. Add 1/8 tsp baking powder at the very end to make the onions sweeter. You can’t add it at the beginning or the onions will break down too much, but adding it at the end lends just the right amount of jamminess.

French onion steak skillet

4 large onions, sliced in ¼ inch slices  
1 Tbsp olive oil
3 Tbsp butter, divided
5 large sprigs of thyme
2½ cups beef stock
¼ tsp salt
1/8 tsp baking soda
1 lb skirt steak, strip steak, flank steak, or tri-tip steak (basically any moderately thin steak) Salt and pepper to taste
½ large baguette, sliced
1 clove garlic, halved
3 oz gruyere cheese, thinly sliced or grated
Flaky sea salt

For the onions:
In a large, ovenproof skillet or pot with a tight fitting lid, heat the olive oil and 1 Tbsp of butter over a medium high flame. Add the onions and thyme, cover, and cook for 3 minutes. If the onions start to burn, turn the heat down slightly (but try to maintain a high heat). After 3 minutes, remove the cover, add ¼ cup of stock, and scrape the browned bits from the bottom of the pan and mix the onions around. Re-cover and cook for another 3 minutes, and then repeat the stock/scrape/mix process. Repeat this 3-minute process until the onions are uniformly soft and brown, about 15-20 minutes.

Turn off the heat and mix in ¼ tsp kosher salt and 1/8 tsp of baking soda. Remove the onions to a separate plate and wipe out the pot.

For the skillet:
Whole the onions are cooking, slice the bread and toast lightly in the toaster. Rub the raw garlic over one side of the bread. Shred the gruyere. Set aside.

When the onions are done and removed to another container, heat the broiler to high.

Melt the other 2 Tbsp of butter in your wiped-out skillet over high heat. Sear the steak for about 3-4 minutes per side. While the steak is seering on one side, season with salt and pepper. Repeat when you flip to the other side.

Turn off the heat and add the cooked onions back to the pan.

Pour 3-4 Tbsp of stock over the onions in the pan. Nestle the slices of bread in the onions around the steak and top with cheese.

Place the entire pan under the broiler until the cheese is bubbly and slightly browned.

Slice the steak to test doneness. Sprinkle with more flaky sea salt and fresh thyme sprigs.

Yield: 2 grown up and 2 kid servings