Straining yogurt is a two-for-one way to get both a tenderizing brining liquid with whey and a thick strained yogurt called labneh. Labneh can be used in dips and dressings, instead of your morning Greek yogurt, in place of cream cheese in desserts, and more.
Per serving:
Line large fine-mesh sieve with a couple of layers of cheesecloth and place on top of large bowl. Add yogurt (go for extra-fresh—check expiry date) to cheesecloth and place in refrigerator for at least 4 hours. Probiotic-rich whey is collected at the bottom and thick strained yogurt (labneh) is left in the sieve.
In medium bowl, combine 3/4 cup (180 mL) whey from above, mustard, lemon zest, and salt. Add chicken and press down to submerge. Cover and refrigerate for at least 2 hours, up to 1 day.
Heat grill pan or cast iron skillet to medium-high. Remove chicken from marinade; discard marinade. Brush grill with avocado oil. Grill chicken for 5 to 6 minutes per side, until juices run clear. A thermometer inserted into thickest part of chicken should read 160 to 165 F (70 to 74 C). Rest for 5 minutes before slicing.
In small bowl, stir together olive oil and balsamic vinegar. To large platter, add greens and top evenly with grain of choice, beet, radishes, and avocado. Top with sliced chicken and drizzle olive oil and balsamic overtop. Serve with lemon wedges.