Amazing Plum Oatmeal Bars With Crumble Topping

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Amazing Plum Oatmeal Bars With Crumble Topping layer a tart plum filling with a crunchy sweet buttery, oat-filled crust seasoned with cinnamon. These bars are sure to be a new summer favorite.

Serve these plum oatmeal squares warm, cold, or at room temperature. Top them with ice cream for an easy summer dessert.

Because they have so little added sugar they also work as plum breakfast bars.

If you like these plum crumble bars you will also want to check out these fresh peach bars.

Cut plum bars scattered on parchment paper.

Why You Will Love This Recipe

Juicy sweet plums are surrounded by buttery crunchy streusel.
This easy recipe uses the same mix for both the crust and topping.
These plum bars make a great breakfast or top them with ice cream for a delicious dessert.

How to Choose the Best Plum

Look for plums that are heavy for their size, smooth, and without blemishes. Avoid plums that are shriveled or have spots and discoloration. Ripe plums will be slightly soft.

You can ripen firm plums in a paper bag at room temperature but you should avoid plums that are excessively hard as they were harvested prematurely and will never ripen properly.

The Best Way to Store Plums

Plums should be ripened at room temperature until they begin to soften. Ripe plums can be refrigerated for up to four days. Before eating allow plums to return to room temperature for maximum juiciness and sweetness.

Ingredients

Old Fashioned Oats: Do not use instant or steel-cut oats. Old-fashioned oats are the perfect size and texture for these bars.

Flour: To make these bars gluten-free use gluten-free oats and substitute almond flour for the all-purpose flour.

White Sugar and Brown Sugar

Baking Powder

Cinnamon

Salt: I add at least a pinch of salt to all of my recipes. Salt complements and intensifies the other flavors. For all of my recipes, I use Morton Kosher Salt which packs more densely than Diamond Crystal Kosher Salt. If you are using Diamond Crystal Kosher Salt you will want to double the amount of salt you add.

Unsalted Butter: I prefer to use unsalted butter when baking. The amount of salt in butter can vary from brand to brand. By using unsalted butter and adding salt seperatly I can control how much salt is added to the recipe,

Vanilla Extract

Plums

Corn Starch: Cornstarch is used to thicken the plumb juice while the bars bake. It does not need to be dissolved in additional liquid and can be sprinkled over the fruit before adding the final layer.

Equipment

Digital Kitchen Scale: Kitchen scales make baking faster and neater. Accuracy matters in baking. Scales are more precise than measuring cups. Too much flour or not enough sugar can dramatically change a recipe. The most accurate way to bake is to measure your ingredients by weight rather than volume.

A kitchen scale also reduces the number of dishes you will need to wash because you are measuring each ingredient directly from the container into the mixing bowl without the use of measuring cups.

This scale from OXO is the one I use after it was recommended by Alton Brown. What makes this scale great is the display pulls out to make viewing measurements easier when using a large bowl.

Mixing Bowls: These are some of my favorite mixing bowls. They come in a huge range of sizes, nest together for easy storage, and are easy to clean.

Cutting Board: This is my favorite cutting board from OXO. It has a rubber edge that keeps the board from sliding around along with a channel around the edge to catch juice keeping my counters clean.

Rubber spatula: For folding batters together, I prefer a stiffer spatula like this one from OXO. It fits comfortably in my hand, is dishwasher safe, and is heat-resistant up to 600 degrees Fahrenheit. Both the handle and head are silicone coated, making it easy to clean and safe to use with my non-stick cookware and bakeware.

9x9 metal baking pan: I prefer light-colored metal pans for baking. Glass or dark-colored metal pans heat unevenly and can cause the edges to overbake or even burn.

Parchment Paper: Line your baking pan with parchment paper allowing the ends to extend beyond the pan on two sides. This will create a sling, allowing you to easily lift the bars from the pan and cut the bars into even squares easily.

Large serrated knife: A large serrated knife makes cutting even clean pieces much easier.

Directions

Line a 9 x 9-inch baking pan with parchment paper allowing the ends to extend over two of the sides, spray with nonstick spray, and set aside. Heat oven to 375 degrees Fahrenheit and position an oven rack at the top of the oven.

Oatmeal butter and sugar mixed in a glass bowl.

Make the crust and topping. In a large mixing bowl, stir together the oats, all-purpose flour, sugar, brown sugar, baking powder, cinnamon, and salt. Add the melted butter and vanilla to the dry ingredients. Stir until crumbly.

Unbaked oatmeal sugar and butter in a metal pan.

Baked oatmeal sugar and butter in a metal pan.

Bake the crust. Press half of the dough into the bottom of the pan in an even layer and bake for 10-12 minutes or until lightly golden brown on the edges.

Pieces of plum layered in a metal baking dish.

Prepare the plum filling. While the crust is baking, chop the plums into 1-inch pieces. Layer the chopped plums over the baked crust and sprinkle with the cornstarch. Top with the remaining crumb mixture.

Bake for 30-40 minutes until the crust is light golden brown.

Cool completely then refrigerate for one hour. Use the parchment paper to lift the bars from the pan for easy cutting and cut them into squares.

Serving Suggestions

Room temperature. Remove the bars from the refrigerator and set them out for about 30 minutes to come to room temperature.
Cold: If you prefer a firmer texture, serve the bars straight from the refrigerator.
Warm: Warm the plum bars in the microwave for about 10 seconds. Serve with a scoop of vanilla ice cream or freshly made whipped cream.

Plum bar on a white plate topped with ice cream.

Storage

Refrigerator

Store the plum bars in the refrigerator in an airtight container for up to one week.

Freezer

Cool the plumb bars completely and cut them into squares.
Place the squares on a wax paper or parchment paper-lined baking sheet and freeze until solid, about 2 hours.
Layer the bars in a storage container separating each layer with sheets of wax paper or parchment paper.
Bars can be frozen for up to 3 months.
To thaw, place in the refrigerator overnight.

Frequently Asked Questions

Do you need to peel the plums?

I don't the tart flavor of the skin provides a nice contrast to the sweet crust.

How do you cut plum bars smoothly?

For neater slices, allow the bars to cool for at least an hour before cutting. This will allow the plum filling to set. Use the parchment paper sling to lift the bars from the baking pan. Use a large serrated knife to easily cut even pieces.

Tips

Make the crumb base/topping ahead of time and store it in the refrigerator or freezer. You can also double the recipe and keep extra in your freezer for future use.
Substitute a good plum jam in place of the fresh plums.
Baking times for all recipes are only suggestions. The actual baking time will vary depending upon your oven. It is helpful to know your oven and worth purchasing an inexpensive oven thermometer. Oven temperatures can vary as much as 50 degrees plus or minus.
Refrigerating the bars for at least an hour before cutting ensures easy clean cuts.
Substitute your favorite stone fruit like peaches, nectarines, or apricots for the plums.

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