The herbed sauce in this grain dish gets a double hit of punchy dairy: Not as sharp as other acidic ingredients, buttermilk lends a unique tang and yogurt brings body and richness.
Step 1
Toast grains in a dry medium heavy pot over medium heat, stirring occasionally, until just slightly darkened and beginning to smell nutty, about 4 minutes. Pour in 4 cups water, then add onion, garlic, lemon zest, and a couple of big pinches of salt; stir to combine. Bring mixture to a boil, then reduce heat to medium-low and simmer, stirring occasionally and skimming any foam from surface as needed, until grains are tender (pull out a few grains and take a bite to test), 35–45 minutes; pluck out and discard onion, garlic, and lemon zest.
Step 2
Meanwhile, purée parsley, dill, buttermilk, and a big pinch of salt in a blender until bright green and smooth. Pour into a medium bowl, add yogurt, and whisk until your arm gets a bit tired—3 minutes should do the trick (whisking the mixture well will ensure that the yogurt doesn’t split and get grainy when you add it to the grains).
Step 3
Pour buttermilk mixture over grains. Increase heat to medium and bring to a bare simmer. Cook just until heated through, about 1 minute. Remove from heat and squeeze in juice from lemon half. Stir well, then taste grains and season with more salt if needed. Skim any foam from surface.
Step 4
Ladle grains into bowls. Drizzle some oil into each bowl and top with coarsely ground pepper.