In a Dutch oven on medium high heat, sauté the chopped onion, carrot, and celery in olive oil until soft. Season with salt and pepper.
Add in some chopped garlic, and the rinsed barley and lentils. Stir for a minute or two until the garlic is fragrant.
Add in tomato, stir until it begins to bubble. Then add in Italian seasoning, salt and pepper, and a bay leaf.Use a clean spoon and taste and adjust the flavor by adding in a bit more salt and pepper to your liking.
Add in 8 cups of vegetable or chicken broth, then cover and bring to a boil.Lower to simmer and cook for about 45 minutes.
Taste again. Add more salt and pepper by the 1/4 teaspoon until you find the sweet spot!
Taste the barley. If the barley feels to firm, cook for another 5 minutes and taste again.
Turn off the heat and add 4 cups of spinach (or kale). Give it a little stir to distribute the veggies and help them wilt. You can omit this step if you aren't a fan of either.
Squeeze in the juice of half a lemon for extra zing and flavor. If you want the broth to be more "soupy" add in 1-2 cups of broth or water to your liking.
It's now ready to serve!