• Before starting, preheat oven to 450˚F. Wash and dry all produce.
• In a large non-stick pan, heat 1/2 tbsp (1 tbsp) oil over medium.
• While the pan heats, using a strainer, rinse leeks to wash away any hidden dirt.
• When hot, add leeks. Cook for 3-4 min, stirring often, until tender. 
• Add 1 tsp (2 tsp) sugar, half the vinegar and 2 tbsp (4 tbsp) water. Season with salt. Cook for 2-3 min, stirring often, until leeks are dark golden and water is absorbed. 
• Remove from heat.
• Transfer to a plate.
• Carefully wipe the pan clean.

• Meanwhile, finely chop parsley.
• Halve bocconcini.
• Halve tomatoes.
• Pat dry with paper towels. Season with salt and pepper.
• Heat a large non-stick pan over medium-high. When hot, add 1/2 tbsp (1 tbsp) oil, then chicken. (NOTE: Don't crowd the pan; cook chicken in 2 batches if needed.) Cook for 1-2 min per side, until golden.
• Transfer chicken to an unlined baking sheet. Roast in the middle of the oven for 12-14 min, until chicken is cooked through.**
• Carefully wipe pan clean.

• Reheat the same pan (from step 1) over medium. 
• When hot, add pine nuts to the dry pan. Toast for 2-3 min, stirring often, until golden. (TIP: Keep your eye on them so they don't burn.) 
• Transfer to a plate.
  

• To the same pan, add 1/2 tbsp (1 tbsp) oil, then half the spinach. Stir for 30 sec, until wilted. Season with salt and pepper.
• Remove from heat.

• On a parchment-lined baking sheet, arrange flatbreads. (NOTE: For 4 servings, use 2 parchment-lined baking sheets.) 
• Spread pesto over flatbreads.
• Thinly slice chicken.
• Top with wilted spinach, caramelized leeks, chicken, bocconcini-tomato mixture, then sprinkle Parmesan over top.
• Bake flatbreads in the middle of the oven until golden and bocconcini has melted, 7-8 min. (NOTE: For 4 servings, bake flatbreads in the middle and top of the oven, rotating sheets halfway through.)

• In a large bowl, whisk together remaining vinegar, 1/4 tsp (1/2 tsp) sugar and 1 tbsp (2 tbsp) oil. Season with salt and pepper.
• Add remaining spinach and remaining tomatoes, then toss to coat.
• Garnish flatbreads with remaining parsley and chili flakes.
• Cut flatbreads into quarters.
• Divide between plates flatbreads and salad between plates.
• Sprinkle pine nuts over salad.

If you've opted to add chicken breasts, pat dry with paper towels. Season with salt and pepper. Heat a large non-stick pan over medium-high. When hot, add 1/2 tbsp (1 tbsp) oil, then chicken. (NOTE: Don't crowd the pan; cook chicken in 2 batches if needed.) Cook for 1-2 min per side, until golden. Transfer chicken to an unlined baking sheet.  Roast in the middle of the oven for 12-14 min, until chicken is cooked through.** Carefully wipe pan clean. Use the same pan to cook pine nuts in step 4.

Thinly slice chicekn. Top flatbreads with chicken when you assemble them.