Blueberry Slab Pie

Ingredients

• 2.25 lb Frozen wild blueberries (High‑quality wild berries, keep frozen until used)
• 0.25 cup Frozen raspberries (Handful, adds a touch of color and extra flavor)
• 0.25 cup Cornstarch (Thickens the filling)
• 0.75 cup Lemon verbena sugar (Granulated sugar infused with dried lemon verbena; if unavailable, use regular sugar + 1 tsp lemon zest)
• 1 tsp Kosher salt (Enhances the blueberry flavor)
• 1 tbsp Ground cinnamon (Warm spice for the filling)
• 1 tbsp Ground ginger (Warm spice for the filling)
• 1 tbsp Ground cardamom (Adds subtle floral note)
• 2 tsp Vanilla extract
• 2 tbsp Fresh lemon juice (Brightens the filling; zest omitted because verbena sugar provides citrus)
• 2 portions All‑butter flaky pie dough (double batch) (See Claire Saffitz’s Flaky All‑Butter Pie Dough recipe; each portion makes one bottom or top crust)
• 1 Large egg (For egg wash (gloss and adhesion))
• 1 tbsp Water (for egg wash)
• 2 tbsp Demerara sugar (Sprinkled on top for sparkle and extra crunch)

Instructions

1. Combine filling ingredients

   In a large bowl, add the frozen blueberries, frozen raspberries, ¼ cup cornstarch, ¾ cup lemon verbena sugar, 1 tsp kosher salt, 1 tbsp each ground cinnamon, ginger, and cardamom, 2 tsp vanilla extract, and 2 tbsp fresh lemon juice. Stir gently until everything is evenly coated.

   Time: PT5M

2. Chill the filling

   Cover the bowl with plastic wrap and place it in the freezer for about 10 minutes so the mixture stays firm for assembly.

   Time: PT10M

3. Prepare the dough

   Make a double batch of the flaky all‑butter pie dough (or use pre‑made dough). After mixing, shape into two discs, wrap in plastic, and chill at least a few hours (overnight is best).

   Time: PT15M

4. Roll out the bottom crust

   On a lightly floured surface, roll one disc to roughly 16 × 12 inches, about ¼‑⅛ in thick. Transfer it onto the porcelain slab, letting it gently sag into the corners.

   Time: PT10M

5. Roll and cut top‑crust strips

   Roll the second disc to a similar size but slightly thicker (about ¼ in). Using a wheel cutter or sharp knife, cut long strips about ½ in wide. Keep the strips chilled while you finish the bottom crust.

   Time: PT10M

6. Make egg wash

   Beat the egg with 1 tbsp water until smooth; no streaks.

   Time: PT2M

7. Add filling to crust

   Remove the frozen filling from the freezer and spread it evenly over the bottom crust, pressing gently to the edges.

   Time: PT5M

8. Brush crust edges

   Using the pastry brush, apply a thin layer of egg wash around the perimeter of the bottom crust.

   Time: PT2M

9. Arrange decorative strips

   Drape the chilled strips over the filling in a staggered, zig‑zag pattern, leaving small gaps to show the fruit underneath.

   Time: PT5M

10. Trim and crimp edges

    Trim excess strip overhang to about ½ in. Fold the bottom crust over the strip edges, then crimp by pinching with thumb and forefinger. Brush the folded edge with more egg wash.

    Time: PT5M

11. Final egg wash and sugar

    Brush the entire top of the pie with a final coat of egg wash, then sprinkle evenly with 2 tbsp demerara sugar.

    Time: PT2M

12. Freeze assembled pie briefly

    Place the slab pie back in the freezer for about 10 minutes until the crust edges feel firm.

    Time: PT10M

13. Preheat oven

    Preheat the oven to 425°F (220°C).

    Time: PT10M

    Temperature: 425°F

14. Bake at high heat

    Place the slab (on a half‑sheet tray to catch drips) in the oven and bake for 20 minutes.

    Time: PT20M

    Temperature: 425°F

15. Reduce temperature and finish baking

    Lower the oven to 350°F (175°C) and continue baking for 40 minutes, or until the crust is deep golden and the filling is bubbling.

    Time: PT40M

    Temperature: 350°F

16. Cool completely

    Remove the pie from the oven and let it cool on a wire rack until completely set (about 30 minutes) before slicing.

    Time: PT30M

Nutrition Facts

Calories

350

Protein

4 g

Carbohydrates

55 g

Fat

15 g

Fiber

4 g

Ingredient Substitutions

• Instead of Frozen wild blueberries: Fresh blueberries (use 2 lb and add extra cornstarch)
• Instead of Frozen raspberries: Fresh raspberries
• Instead of Cornstarch: Arrowroot powder, Tapioca starch
• Instead of Lemon verbena sugar: Granulated sugar + lemon zest
• Instead of Kosher salt: Sea salt
• Instead of Ground cinnamon: Ground nutmeg
• Instead of Ground ginger: Ground cinnamon
• Instead of Ground cardamom: Ground allspice
• Instead of Vanilla extract: Almond extract (use half amount)
• Instead of Fresh lemon juice: Lemon zest + 1 tsp white wine vinegar
• Instead of All‑butter flaky pie dough (double batch): Store‑bought pie crust
• Instead of Large egg: Milk wash (1 tbsp milk)
• Instead of Demerara sugar: Brown sugar

Equipment Needed

• Porcelain baking slab (13" × 9")
• Rolling pin
• Bench scraper
• Ruler or pizza cutter guide (optional)
• Wheel cutter or sharp knife (optional)
• Pastry brush
• Food processor (optional for verbena sugar) (optional)
• Mixing bowls
• Freezer
• Oven
• Half‑sheet tray (for drip pan)
• Bread knife (or sharp serrated knife)

Critical Steps — Do Not Skip

• Keep the berry filling frozen until assembly.
• Maintain a cold crust (chill and brief freeze) before baking.
• Start baking at a high temperature (425°F) then reduce to finish.

Chef Tips from the Video

• For an extra citrus punch, add a pinch of lemon zest to the filling in addition to the verbena sugar.
• If you don’t have a porcelain slab, a heavy‑duty cast‑iron skillet works well and also provides a crisp bottom.
• Use a light dusting of flour on the rolling surface to prevent sticking without over‑flouring the dough.

Troubleshooting

Storage

Refrigerator: Cover tightly; lasts up to 3 days.

Freezer: Wrap the whole slab pie in plastic and foil; freeze up to 2 months.

Room temperature: Can sit at room temperature for up to 2 hours after cooling.

Make-Ahead Tips

• The flaky all‑butter dough can be prepared up to 2 days ahead and kept wrapped in the fridge.
• The berry filling can be mixed and frozen for up to 1 month; thaw slightly before assembling.