Summary

Instructions

1. 1

   Preheat oven to 350°F (177°C). Line a 9-inch square baking pan with parchment paper, leaving an overhang on the sides for easy removal.

2. 2

   Make the crust: In a medium bowl, whisk together the flour, 1 cup (85g) oats, brown sugar, baking powder, lemon zest, cinnamon, and salt. Add the melted butter and stir until the mixture resembles moist, crumbly sand with no dry spots.

3. 3

   Press 2/3 of the mixture (about 2 cups/345g; doesn’t need to be exact) firmly into the prepared pan to form the crust. Bake for 10 minutes, then remove from the oven and let cool slightly.

4. 4

   Make the filling: In a saucepan over medium heat, combine the blueberries, granulated sugar, cornstarch, and lemon juice. Cook and stir for 2–3 minutes until the sugar and cornstarch begin to dissolve and the berries look evenly wet. Remove from heat and stir in the lemon zest.

5. 5

   Pour/spread the blueberry filling evenly over the warm crust.

6. 6

   Stir the remaining 2 Tablespoons oats into the reserved crumble mixture, then sprinkle it evenly over the filling and lightly press down.

7. 7

   Bake for 45–55 minutes, or until the top is lightly browned and the filling is bubbling around the edges.

8. 8

   Cool the pan completely on a wire rack. For neat squares, optionally cover and refrigerate up to 1 day before cutting. Lift out using parchment overhang, slice into squares, and serve. Store leftovers covered at room temperature up to 2 days or in the refrigerator up to 1 week.