Description
Soft, chewy oatmeal cookie rounds sandwiched with a stable vanilla marshmallow-style cream filling—made for stacking and lunchbox desserts.
Ingredients
Scale
- For the oatmeal cookies:
- 1 1/4 cups (150 g) all-purpose flour
- 3/4 cup (90 g) old-fashioned rolled oats
- 1 tsp baking soda
- 1/2 tsp fine salt
- 1 tsp ground cinnamon (optional, light)
- 1/2 cup (113 g) unsalted butter, softened
- 3/4 cup (150 g) packed light brown sugar
- 1/4 cup (50 g) granulated sugar
- 1 large egg
- 1 tsp vanilla extract
- 1/4 cup (60 ml) unsweetened applesauce (see note for substitutions)
- 1/2 cup (120 g) toasted walnuts, finely chopped (optional)
- 1–2 tbsp (8–16 g) water or milk, as needed to adjust dough
- For the stable vanilla marshmallow-style filling:
- 1/2 cup (120 ml) water
- 1 cup (200 g) granulated sugar
- 1/4 cup (60 ml) light corn syrup
- 2 large egg whites (about 60–70 g total)
- 1/4 tsp fine salt
- 2 tsp vanilla extract
- 1/2 cup (113 g) unsalted butter, softened
- Optional: 1–2 tbsp (8–16 g) toasted walnuts, very finely chopped, to fold into filling (optional, for extra crunch)
- Optional finishing:
- Extra toasted walnuts for sprinkling (optional)
Instructions
- Cookies: Toast oats (optional for deeper flavor): Spread rolled oats on a baking sheet and toast at 325°F (163°C) for 6–8 minutes until fragrant. Cool.
- Prep: Line 2 baking sheets with parchment paper. Set aside.
- Mix dry ingredients: In a bowl, whisk flour, oats, baking soda, salt, and cinnamon (if using).
- Cream wet ingredients: In a second bowl, beat butter, brown sugar, and granulated sugar until smooth and lighter in color (about 1–2 minutes).
- Add egg and flavor: Beat in the egg and vanilla until combined.
- Combine: Add the dry ingredients to the wet mixture. Mix just until a thick dough forms. Stir in walnuts (if using).
- Adjust texture: If the dough feels stiff/dry, add 1–2 tbsp water or milk as needed. It should be scoopable and thick.
- Chill: Refrigerate the dough 30–60 minutes for thicker, bakery-style rounds.
- Scoop and shape: Scoop mounded tablespoons (about 25–30 g each) and place 2 inches (5 cm) apart. Gently roll into rough rounds if needed.
- Bake: Bake at 350°F (177°C) for 10–12 minutes, rotating once if your oven has hot spots. Doneness cue: edges look set and matte; centers look slightly underdone but puffed.
- Cool on sheet: Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
- Stable vanilla marshmallow-style filling: Start syrup: In a small saucepan, combine water, granulated sugar, and corn syrup. Place over medium heat.
- Whip egg whites: When the syrup is actively simmering, add egg whites and salt to a clean bowl. Whip to soft peaks.
- Cook syrup to stage: Use a candy thermometer; cook syrup to 240°F (116°C). Syrup should be clear and thickening.
- Pour and whip: With mixer running on medium-high, carefully pour the hot syrup in a thin stream into the egg whites. Continue whipping 5–7 minutes until the bowl feels mostly cool and the meringue is glossy, thick, and holds soft peaks.
- Add butter: Add softened butter a few tablespoons at a time, whipping after each addition. If it looks curdled, keep whipping—it usually smooths out as the mixture emulsifies.
- Finish: Beat in vanilla (and optional finely chopped toasted walnuts, if using). Stop when the filling is thick, fluffy, and holds shape.
- Assemble: Pair cookies: Match cookies by size. Turn half of them (bottom-up) so you pipe filling on the flat side.
- Fill: Pipe or spread filling onto the flat side of each paired cookie, then sandwich with the remaining cookies.
- Set: Refrigerate assembled pies 20–30 minutes so the filling firms slightly for stacking.
- Serve: Enjoy chilled or at cool room temperature.
Notes
1) Applesauce substitution: For a similar moisture balance, you can use an equal amount of plain Greek yogurt (full-fat if possible). If you replace with yogurt, dough may be slightly looser—chill as needed.
2) Piping tip: A wide round tip (like 1A/1A-ish) creates bakery-like layers.
3) Make-ahead: Cookies can be baked 1–2 days ahead and stored airtight. Filling can be made up to 2 days ahead; re-whip until spreadable before assembling.
4) Shelf life: Assembled pies keep best refrigerated in an airtight container.