Experiment No. 202 — Sweet Potato Pie Crust Cookie
Experiment No. 202 — Sweet Potato Pie Crust Cookie
Scope
Recreate a pie–cookie hybrid where a flaky butter-layered crust supports a smooth sweet-potato custard. This experiment studies starch structure, fat layering, and controlled moisture to hold both filling and marshmallow without collapse.
Objective
Engineer a crust that behaves as both cookie and pie shell while producing a glossy sweet-potato filling stabilized by starch, fat, and sugar. Anchor a marshmallow plug using a carved well to prevent melting displacement during broiling.
Yield & Time
Yield: ~12–14 cookies (≈ 1.15 kg total dough + filling)
Prep: 35–40 min | Chill: 10–15 min | Bake: 10–15 min | Broil: 1–3 min
Formula – Weight, Volume, Ratio %
Weight = reproducibility Volume = accessibility Ratio % = structural balance of each phase
Sweet Potato Pie Filling (100%)
Sweet potato (steamed, pureed): 400 g | 2 medium | 44.9%
Coconut milk (full-fat): 180 g | ¾ cup | 20.2%
Brown sugar: 100 g | ½ cup | 11.2%
Cornstarch: 32 g | ¼ cup | 3.6%
Maple syrup: 60 g | ¼ cup | 6.7%
Vanilla extract: 5 g | 1 tsp | 0.6%
Cinnamon: 2 g | 1 tsp | 0.2%
Pumpkin pie spice: 1 g | ½ tsp | 0.1%
Allspice: 0.5 g | ¼ tsp | 0.06%
Salt: 3 g | ½ tsp | 0.3%
🔸 Optional Filling Adjustment
If you prefer a smaller mound of filling on each cookie, you can cut the amount you scoop into the divots in half during assembly.
If you decide to make the full batch of filling, any extra can be served as a warm side topping for anyone who wants more.
Procedure (Filling)
Steam diced sweet potatoes 20–25 minutes until tender. Add remaining ingredients in listed order and purée until smooth and glossy. Cool completely to allow starches to set.
Crust Cookie Dough (100%)
All-purpose flour: 208 g | 1½ cups | 59.6%
Sugar: 4 g | 1 tsp | 1.1%
Salt: 1.5 g | ¼ tsp | 0.4%
Vegan butter (cold): 113 g | ½ cup | 32.4%
Cold water: 45 g | 3 Tbsp | 12.9%
Procedure (Crust Dough)
Cut cold vegan butter into small cubes and chill. Add butter to food processor and pulse until pea-sized.
Add flour, sugar, and salt; pulse 3–5 times to disperse.
Add cold water 1 tablespoon at a time, pulsing 4–6 times between additions:
• After 1 Tbsp: mixture looks sandy
• After 2 Tbsp: crumbs thicken
• After 3 Tbsp: clumps form and hold when pressed
Use a 4th Tbsp only if dough still does not hold together.
Bring dough together, wrap, chill 10–15 minutes. Roll to ¼-inch and cut 2.5–3-inch rounds.
Composite System
Filling: 783.5 g (68%)
Crust: 371.5 g (32%)
Total: 1,155 g (100%)
Protocol — Assembly & Bake
Shape: Place dough rounds on parchment. Press the center to create a shallow divot with a ½-inch border.
Fill: Spoon 2–4 Tbsp filling into each divot and smooth lightly.
Brush: Mix 1 Tbsp vegan butter + 1 Tbsp brown sugar + pinch cinnamon. Brush entire cookie surface.
Create Well + Marshmallow Plug:
Carve a small well in the center (quarter-sized). Add 1–2 Tbsp marshmallow fluff.
Skipping the well will cause fluff to slide off during baking.
Bake: 350°F (177°C) for 10–15 minutes until edges lightly golden.
Broil: Broil on High for 1–3 minutes to toast marshmallow.
Cool: Rest 10–15 minutes to allow structure to set.
Analytical Notes
Filling ratio: ≈ 45% starch / 20% fat
Crust ratio: ≈ 60:40 flour:fat
Target Aw: 0.65–0.70
Predicted pH: 5.8–6.2
Bake loss: 8–10%
Variants
Brown Butter Crust — Replace vegan butter with browned plant butter.
Maple Pecan — Add pecans and maple drizzle before broil.
Mini Tarts — Press dough into mini muffin tins.
Gluten-Free — 130 g GF flour + 75 g oat flour; same hydration.
