Pistachio-Cherry Crumble

INGREDIENTS

• 1/2 cup plus 1 tablespoon light brown sugar, divided
• 1/4 teaspoon ground cardamom
• 5 cups pitted cherries (2 pounds whole or 1 1/2 pounds pitted), thawed if frozen
• 1/4 teaspoon salt
• 1 tablespoon fresh lemon juice
• 4 walnuts, shelled
• 1/3 cup rolled oats
• 1/2 cup shelled, unsalted pistachios
• 4 tablespoon unsalted butter, melted
• Unsalted butter for greasing pan
• 1/3 cup plus 1 tablespoon all-purpose flour, divided