Strawberry-Rhubarb Crumble Bars

INGREDIENTS

3 cups

all-purpose flour

1 cup

white granulated sugar

1 tsp

baking powder

1/2 tsp

ground cinnamon

1/4 tsp

kosher salt

1 cup

or 2 sticks) unsalted butter, cold

large egg

2 cups

diced 1/4-inch chunks) rhubarb (2 to 3 thick stalks or 5 to 6 thin stalks or a little over 1/2 pounds)

2 cups

diced (1/4-inch chunks) strawberries (3/4 pounds)

3 tbsp

white granulated sugar

1 tbsp

cornstarch

1 tbsp

lemon juice