Author: The Kilted Chef

Ingredients
Crust & Topping

• 1 1/2 cups (188g) all-purpose flour
• 1 cup (85g) + 2 Tbsp old-fashioned rolled oats, divide
• 1/2 cup (100g) packed light or dark brown sugar
• 1 tsp baking powder
• 1 tsp lemon zest
• 1/4 tsp ground cinnamon
• 1/8 tsp salt
• 10 Tbsp (142g) unsalted butter, melted

Filling

• 4 1/2 cups (640g) frozen wild blueberries (do not thaw)
• 1/2 cup (100g) granulated sugar
• 2 1/2 Tbsp (20g) cornstarch (increase slightly to account for extra liquid)
• 1 Tbsp lemon juice
• 2 tsp lemon zest

Instructions

1. Prep the Pan – Preheat oven to 350°F (177°C). Line a 9×13-inch pan with parchment paper, leaving an overhang.
2. Make the Crust & Topping – Whisk together flour, 1 cup oats (reserve 2 Tbsp), brown sugar, baking powder, lemon zest, cinnamon, and salt. Stir in melted butter until crumbly.
3. Form the Base – Press two-thirds of the mixture firmly into the prepared pan for the crust. Reserve the remaining one-third for topping.
4. Prepare the Filling – Toss frozen wild blueberries with sugar, cornstarch, lemon juice, and zest. Spread evenly over the crust.
5. Add Topping & Bake – Mix reserved 2 Tbsp oats into the leftover crumb mixture, then sprinkle over blueberries. Bake 50–55 minutes, until golden and bubbling (tent with foil if browning too quickly).
6. Cool & Slice – Cool completely in the pan for at least 3 hours. Lift out with parchment and slice into squares.