Wash and dry all produce. Add vegetable stock powder, 1 1/4 cups (2 1/2 cups) water and 1 tbsp (2 tbsp) butter to a medium pot. Cover and bring to a boil over high heat.Once boiling, add rice, then reduce heat to low. Cover and cook until rice is tender and liquid is absorbed, 12-14 min.Remove the pot from heat. Set aside, still covered.

Zest, then juice half the lemon. Cut remaining lemon into wedges.Thinly slice cucumber.Cut tomato into 1/4-inch pieces.Roughly chop dill.

Heat a large non-stick pan over medium-high heat.While pan heats, pat chicken dry with paper towels. Season with salt and pepper.When hot, add 1 tbsp (2 tbsp) oil, then chicken. Reduce heat to medium. Cover with a lid and cook, flipping halfway until golden-brown and cooked through, 3-4 min per side. **

Meanwhile, add sour cream, lemon zest, half the dill, half the feta and 1/4 tsp (1/2 tsp) sugar to a medium bowl. Season with salt and pepper, then stir to combine.Add 2 tsp (4 tsp) lemon juice, 1/2 tbsp (1 tbsp) oil, and 1/8 tsp (1/4 tsp) sugar to a large bowl. Season with salt and pepper, then stir to combine.Add cucumbers, tomatoes and spring mix to the bowl with dressing. Toss to coat.

Fluff rice with a fork, then stir in remaining dill.Divide rice, chicken and salad between plates.Dollop feta-dill sauce over chicken.Sprinkle remaining feta over salad.Squeeze a lemon wedge over top, if desired.