• Before starting, remove 2 tbsp (4 tbsp) butter from the fridge and set aside to come up to room temperature.
• Preheat the oven to 450°F.
• Wash and dry all produce.
• Heat a medium pot over medium.
• While the pot heats, peel, then cut onion into 1/8-inch slices.
• When the pot is hot, add 1/2 tbsp (1 tbsp) butter, then onions. (NOTE: Save the softened butter for step 4.) Cook for 5-7 min, stirring occasionally, until golden.
• Reduce heat to medium-low, then add half the balsamic glaze. Season with salt and pepper. Cook for 4-6 min, stirring occasionally, until onions are dark brown. Remove the pot from heat.

• Meanwhile, halve buns.
• Core, then cut apple into 1/4-inch slices.
• Cut tomato into 1/2-inch pieces.
• Cut brie into 1/4-inch slices.
• To a large bowl, add remaining balsamic glaze and 1/2 tbsp (1 tbsp) oil. Season with salt and pepper, then whisk to combine. 
• Pat chicken 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. Sear for 3-4 min per side, until chicken is golden and cooked through.** Transfer to a plate and cover to keep warm.

• Heat the same pan over medium-high. 
• When hot, add 1/2 tbsp (1 tbsp) butter, then swirl the pan until melted.
• Add three-quarters of the apples, then sprinkle with 1/4 tsp (1/2 tsp) sugar. Cook for 1-2 min, stirring occasionally, until warmed through. 
• Transfer apples to a plate to cool.

• Meanwhile, spread 2 tbsp (4 tbsp) softened butter on cut sides of buns.
• On a parchment-lined baking sheet, arrange bottom buns, cut-side up. Set top buns aside.
• Toast bottom buns in the top of the oven for 3-5 min, until warmed. (TIP: Keep an eye on them so they don't burn.) 

• Spread Dijon on toasted bottom buns. Top with warm apples, chicken and caramelized onions, then brie.
• On the same parchment-lined baking sheet, arrange assembled bottom buns and buttered top buns, cut-side up. 
• Toast in the top of the oven for 3-5 min, until brie is slightly melted. (TIP: If you want the brie to be melted more, continue toasting until desired doneness.) 

• To the bowl with vinaigrette, add spinach, tomatoes and remaining apples. Toss to combine. 
• When brie is slightly melted, spoon fig spread over top buns, then close melts. Halve crosswise, if you like.
• Divide melts and salad between plates.
• Sprinkle salad topping mix over salad.

If you've opted to add chicken tenders, 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. Sear for 3-4 min per side, until chicken is golden and cooked through.** Transfer to a plate and cover to keep warm. Use the same pan to cook apples in step 3.

Top bottom buns with chicken when you assemble them.