Description

Craving a sweet-tart, gluten-free dessert that’s perfect for spring or summer? Gluten-Free Raspberry Rhubarb Crumble Bars combine a buttery oat crust with a vibrant raspberry-rhubarb compote, topped with a crunchy crumble.

Ingredients

Scale

Compote

Rhubarb (2 cups, 225 grams, diced, fresh or frozen): Provides tartness and a juicy texture; pairs perfectly with raspberries.
Organic Raspberries (1¼ cups, 170 grams, fresh or frozen): Adds sweet-tart flavor and vibrant color.
Raw Cane Sugar (⅓ cup + 1 tablespoon): Sweetens the tart fruits and helps thicken the compote.
Zest and Juice of One Lemon (~1 teaspoon zest, 2-3 tablespoons juice): Enhances tartness and brightens flavors.
Cornstarch or Tapioca Starch (3 teaspoons): Thickens the compote for a jammy consistency.
Vanilla Extract (½ teaspoon): Adds warmth and depth to the filling.

Base and Crumble

Gluten-Free Old Fashioned Oats (¾ cup, 80 grams): Provides chewy texture and hearty flavor; use certified gluten-free.
Oat Flour (1 cup, 100 grams): Adds structure and a nutty, gluten-free base.
Lightly Packed Brown Sugar (½ cup): Brings caramel-like sweetness and helps crisp the crust.
Tapioca Starch (1 tablespoon, or cornstarch): Enhances crispiness and binds the base.
Baking Powder (1¼ teaspoons): Ensures a light, tender crust.
Sea Salt (¼ teaspoon): Balances sweetness and enhances flavors.
Cinnamon (¼ teaspoon): Adds subtle warmth to the crumble.
Melted Organic Vegetable Shortening (½ cup, e.g., Nutiva coconut/palm oil spread, or butter): Binds the crust and crumble, adding richness; shortening keeps it dairy-free.

Substitutions and Variations

Rhubarb: Swap for additional raspberries or strawberries (maintain 225 grams); adjust sugar down by 1 tablespoon if sweeter fruit is used.
Raspberries: Use blackberries or mixed berries; frozen works well (no need to thaw).
Raw Cane Sugar: Replace with granulated sugar or coconut sugar; coconut sugar darkens flavor slightly.
Lemon Zest/Juice: Use orange zest/juice or 1 teaspoon apple cider vinegar for tartness.
Cornstarch/Tapioca Starch: Swap interchangeably (same amount); arrowroot powder works too.
Vanilla Extract: Omit or use ¼ teaspoon almond extract for a twist.
Oats/Oat Flour: Ensure certified gluten-free; replace oat flour with almond flour (100 grams) for a nuttier base, but adjust shortening to ⅓ cup.
Brown Sugar: Use coconut sugar or granulated sugar; reduce to ⅓ cup for less sweetness.
Shortening/Butter: Swap for melted coconut oil, vegan butter, or regular butter (not dairy-free); coconut oil may solidify when chilled.
Cinnamon: Replace with nutmeg, cardamom, or omit for a plainer crumble.
Add-Ins: Mix ¼ cup chopped nuts (e.g., almonds, pecans) or 2 tablespoons shredded coconut into the crumble for extra crunch.

Pro Tip: Weigh ingredients (e.g., 80 grams oats, 225 grams rhubarb) for precision, as gluten-free baking benefits from accuracy. Use certified gluten-free oats to avoid cross-contamination; dice rhubarb finely for even cooking in the compote.

Essential Equipment

Heavy-Bottomed Saucepan: For cooking the compote evenly without burning.
8×8-Inch Baking Pan: For baking the bars; square shape ensures even layers.
Parchment Paper: For lining the pan to prevent sticking and easy removal.
Large Mixing Bowl: For combining base and crumble ingredients.
Whisk: To blend dry ingredients smoothly.
Spatula or Spoon: For pressing crust and mixing.
Fork: For pricking the crust before baking.
Cooling Rack: For cooling bars to maintain texture.

Pro Tip: Cut parchment to overhang the pan for easy lifting; lightly grease the pan before lining to secure parchment.

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Instructions

Make the Compote:
- In a heavy-bottomed saucepan, combine 2 cups (225 grams) diced rhubarb, 1¼ cups (170 grams) raspberries, ⅓ cup + 1 tablespoon raw cane sugar, zest and juice of one lemon.
- Bring to a hard boil over medium heat, stirring to dissolve sugar, then reduce to a simmer for 10 minutes.
- Add 3 teaspoons cornstarch or tapioca starch, stir to dissolve, and cook for 3 minutes more until slightly thickened.
- Stir in ½ teaspoon vanilla extract, remove from heat, and cool for 15 minutes.
- Tip: Stir frequently to prevent sticking; compote should be jammy but not overly thick (it sets more when baked).
Prepare the Oven and Base:
- Preheat oven to 350°F (177°C).
- In a large mixing bowl, whisk 1 cup (100 grams) oat flour, ¾ cup (80 grams) gluten-free old fashioned oats, ½ cup lightly packed brown sugar, 1 tablespoon tapioca starch, 1¼ teaspoons baking powder, ¼ teaspoon sea salt, and ¼ teaspoon cinnamon.
- Stir in ½ cup melted organic vegetable shortening (or butter) until no white streaks remain and the mixture is crumbly.
- Tip: Mix thoroughly to ensure even distribution; use a fork to break up clumps for a uniform crumble.
Form the Crust:
- Line an 8×8-inch baking pan with parchment paper, leaving overhang for easy removal.
- Press a heaping cup of the oat mixture firmly into the pan using the back of a spatula or spoon to create a smooth, even crust.
- Prick the crust with a fork 5-6 times to prevent puffing.
- Tip: Press firmly for a sturdy base; a spoon helps smooth edges and corners.
Bake the Crust:
- Bake the crust at 350°F for 12 minutes, until fragrant and lightly browned.
- Remove from oven and let cool for 10 minutes.
- Tip: Check at 10 minutes to avoid over-browning; cooling helps the crust set before adding compote.
Assemble and Bake:
- Spread 1¼ cups of the cooled rhubarb-raspberry compote evenly over the crust.
- Sprinkle the remaining oat mixture over the compote to form a crumble topping.
- Bake for 25-30 minutes, until the topping is golden brown and the compote is bubbling slightly.
- Tip: Spread compote gently to avoid disturbing the crust; crumble topping loosely for texture.
Cool and Chill:
- Remove from oven and let cool on a cooling rack for 1 hour.
- Refrigerate for at least 1 hour (or overnight) to firm up for clean slicing.
- Lift bars out using parchment overhang, cut into 9-16 squares, and serve chilled or at room temperature.
- Tip: Chilling is key for sturdy bars; use a sharp knife for clean cuts.

Cooking Tips:

Compote Consistency: Cook until thickened but still spreadable; it firms up during baking and chilling.
Prevent Soggy Crust: Cool the crust and compote before assembling; prick crust to release steam.
Even Baking: Rotate the pan halfway through the final bake for uniform browning; tent with foil if topping browns too quickly.