Preheat oven to 425°F. Toss mushrooms, tomatoes, shallots, 2 tablespoons of oil and ½ teaspoon of salt on a baking sheet. Roast until mushrooms are golden brown and tomatoes are deflated, about 15 minutes.
Whisk dill, parsley, lemon juice, honey, red pepper flakes ½ cup of oil and ½ teaspoon of salt in a bowl and set aside.
Bring broth to a boil in a large pot over medium-high heat. Add cooked grains and let simmer for 5 minutes. Add mushroom mixture and let simmer 5 more minutes. Season with salt.
Toss kale, garlic and remaining oil on the same sheet the mushrooms were on and arrange in a single layer. Roast until kale is wilted and crisp in places, about 4 minutes.
Divide soup among bowls and top with kale mixture.