Heat oven to 350 F.

To make bagel croutons: Cut bagels into 3/4-inch cubes. In bowl, melt butter; stir in brown sugar and salt. Toss bagel cubes in butter mixture.

Spread on baking sheet and bake 15-18 minutes, flipping once, until golden and crisp. Let cool.

To make berry salad: In large bowl, combine sliced strawberries; blueberries; raspberries, if desired; lemon zest; and lemon juice. Toss gently.

To make berry dressing: Place reserved strawberries in bowl. Add brown sugar and salt. Using fork or potato masher, mash until juicy and chunky.

To assemble panzanella salad: Add cooled bagel cubes to berry salad. Pour in mashed strawberry dressing. Toss slightly so bread absorbs juice.

Let sit 5-10 minutes so bagel pieces soften while staying textured.

Serve in bowls with yogurt, poppy seeds and mint leaves, if desired.