Strawberry Rhubarb Ginger Crumb Bars

Ingredients

• 3/4 cup oat flour
• 1-1/2 cups all-purpose flour
• 1/2 cup sugar
• 1/4 cup brown sugar
• 3/4 tsp baking powder
• 1/4 tsp salt
• Zest of half a lemon
• 3/4 cup (1-1/2 sticks or 6 ounces) cold unsalted butter, cubed
• 1 large egg
• 2 cups ½-inch slices of rhubarb
• 2 cups sliced strawberries
• 2 Tbsp crystallized ginger
• Juice of half a lemon
• 1 tsp vanilla extract
• 1/2 cup brown sugar
• 4 tsp cornstarch