Sour Cream Raisin Bars with Oat Crumb Topping
Chewy plumped raisins folded into a silky sour cream custard filling, sandwiched between buttery oat-brown sugar crumble layers. This vintage bar cookie combines tart custard with sweet raisins and a crunchy-textured topping, perfect for potlucks, bake sales, or afternoon coffee. The cooked filling method ensures a dense, fudgy center distinct from typical custard bars.
Ingredients
- 2 cup raisins
- 1 ½ cup water
- 1 ½ cup all-purpose flour
- 1 ½ cup old-fashioned rolled oats
- 1 cup brown sugar, firmly packed
- ¾ cup butter, softened
- 1 teaspoon baking soda
- 1 ½ cup sour cream
- 1 cup sugar
- 3 egg yolks, largecornstarch slurry (2 tbsp cornstarch + 3 tbsp water)replace 3 yolksveganegg-freeeggs-free
filling may be slightly less custardy
Full guide → - 3 tablespoon cornstarch
Instructions
- 1
Heat oven to 350°F.
- 2
Combine raisins and water in saucepan. Cook over medium heat until soft and plump, about 10-12 minutes. Drain and cool completely, about 30 minutes.
- 3
Mix flour, oats, brown sugar, softened butter and baking soda in bowl. Beat until mixture resembles coarse crumbs.
- 4
Press 3 cups crumb mixture firmly onto bottom of ungreased 13x9-inch baking pan.
- 5
Whisk sugar, sour cream, egg yolks and cornstarch in saucepan. Cook over low heat, stirring occasionally, until mixture comes to a boil, about 15-20 minutes. Boil for 1 minute. Remove from heat and stir in drained raisins.
- 6
Spread filling evenly over crust. Sprinkle remaining crumb mixture over top.
- 7
Bake until lightly browned, 25-35 minutes. Cool completely before cutting into bars.
Tips
Cool raisins completely before filling assembly to prevent premature cooking of egg yolks and ensure distinct filling layer.
Press crumb base firmly with fingers or bottom of measuring cup for a stable foundation that won't shift when filling is spread.
Good to Know
Covered airtight container at room temperature up to 5 days. Refrigerate up to 1 week.
Prepare and assemble bars up to 1 day ahead. Bake on day of serving for best texture contrast between crust and topping.
Room temperature or slightly chilled. Cut into 24-32 bars depending on preference.
Common Mistakes
Do not skip cooling raisins to avoid scrambling egg yolks in filling.
Do not underbake crumb base to avoid soggy bottom layer after filling is added.
Do not overbake filled bars to avoid drying out the custard-like filling.
Substitutions
Dairy-Free Swaps
Vegan Options
filling may be slightly less custardy
Full guide →FAQ
Can I use whole eggs instead of yolks only?
Yes, use 2 whole eggs as substitute. Filling will be slightly less rich and may set firmer. Increase cornstarch to 4 tablespoons if texture becomes too runny.
What if my filling breaks or curdles during cooking?
Slow heat and constant stirring prevent breaking. If curdling occurs, remove from heat immediately and whisk vigorously. Strain through fine mesh if necessary. Curdled filling will still taste good but texture may be slightly grainy.
Can I freeze these bars?
Yes, freeze up to 3 months in airtight freezer container with parchment between layers. Thaw at room temperature 2-3 hours before serving. Freezing may slightly soften the crumb texture.