Wrap one 10-oz. plan frozen sliced spinach, defrosted, in a tidy kitchen area towel and twist and capture towel firmly over the sink to expel as much liquid as possible.
Action 2
Melt 2 Tbsp. saltless butter in a medium Dutch oven or other heavy pot over medium-high heat. Include spinach and 1/2 cup carefully sliced herbs (such as cilantro, parsley, and/or dill) and season with kosher salt. Cook, stirring periodically and separating spinach, till mix is integrated and spinach and herbs are a little darkened in color, about 4 minutes. Transfer to a bowl.
Action 3
Heat 3 Tbsp. extra-virgin olive oil in very same pot over medium-high. Include 3 medium onions, very finely sliced, and season with salt. Cook, stirring sometimes, till gently browned and frizzled around the edges, 9– 12 minutes. Include 5 garlic cloves, very finely sliced, and cook, stirring typically, till softened and aromatic, about 1 minute. Include 1 Tbsp. ground coriander, 2 tsp. ground cumin, 1/2 tsp. crushed red pepper flakes, and a couple of grinds of newly ground black pepper. Cook, stirring typically, up until integrated, about 1 minute.
Action 4
Include 2/3 cup basmati rice, 2/3 cup French green lentils, 4 cups low-sodium veggie broth, 2 tsp. Diamond Crystal or 1 1/4 tsp. Morton kosher salt, and 6 cups water; stir to integrate. Boost heat to high and bring soup to a boil. Minimize heat so soup is at a simmer and cook up until rice is prepared through and lentils hurt (they will still maintain a little bit of bite), 30– 35 minutes.
Action 5
Stir spinach mix into soup and cook, stirring frequently, up until integrated and heated up through, about 3 minutes. Get rid of pot from heat and include juice of 1 lemon and staying 2 Tbsp. saltless butter; stir till butter is melted. Taste soup and season with salt and black pepper.
Action 6
Mix 1 cup plain whole-milk yogurt, a huge pinch of salt, and staying 2 Tbsp. extra-virgin olive oil in a little bowl to integrate. Ladle soup into bowls and leading each with a spoonful of yogurt mix to serve.