Blueberry Buckle for a 9×13-ish Foil Pan

From the kitchen of Jay Furr

Coffee-cake style buckle made for a donor party, using frozen Wyman’s wild Maine blueberries.

 

Yield: One 9×13-ish disposable foil pan (about 20-24 squares, depending on how you cut it)
Oven: 350 F
Bake time: 60-75 minutes (start checking at 55)
Cooling time: At least 1 1/2 to 2 hours before cutting
Pan note: Set the foil pan on a sheet pan before filling, baking, and transporting

Ingredients

Crumb Topping

• 1 1/2 cups all-purpose flour (180 g)
• 3/4 cup packed brown sugar (150 g)
• 1/4 cup granulated sugar (50 g)
• 1 tsp ground cinnamon
• 1/2 tsp kosher salt (or 1/4 tsp table salt)
• 10 Tbsp cold unsalted butter (140 g), cut into small pieces

Blueberries

• 6 cups frozen wild blueberries (about 2 lb / 900 g), straight from the freezer
• 2 Tbsp all-purpose flour
• 1 Tbsp cornstarch

Cake Batter

• 3 cups all-purpose flour (360 g)
• 2 tsp baking powder
• 1/2 tsp baking soda
• 3/4 tsp kosher salt (or 1/2 tsp table salt)
• 1 cup (2 sticks) unsalted butter, softened
• 1 1/4 cups granulated sugar (250 g)
• 3 large eggs
• 2 tsp vanilla extract
• Zest of 1 lemon (optional, but very good here)
• 1 cup buttermilk (240 ml), or 1 cup milk plus 1 Tbsp lemon juice/vinegar

 

Method

1. Preheat oven to 350 F. Put your foil pan on a sheet pan. Grease the foil pan well (butter or spray) and lightly flour it.
2. Make the crumb topping: In a medium bowl, mix flour, brown sugar, granulated sugar, cinnamon, and salt. Cut in the cold butter with a fork, pastry cutter, or your fingers until you have coarse crumbs with some pea-sized clumps. Refrigerate while you make the batter.
3. Prep the blueberries: Toss the frozen blueberries with 2 Tbsp flour and 1 Tbsp cornstarch. Keep them frozen until you are ready to use them.
4. Whisk together the dry ingredients for the batter: flour, baking powder, baking soda, and salt.
5. In a large bowl, cream the softened butter and sugar until lighter and fluffy. Add eggs one at a time, mixing after each addition just until incorporated.
6. Stir in vanilla and lemon zest (if using).
7. Add the dry ingredients in 3 additions, alternating with the buttermilk (start and end with dry). Mix just until combined. The batter will be fairly thick.
8. Fold in about 4 cups of the frozen blueberries. Do not overmix unless you want lavender batter (which is pretty, but not the plan).
9. Spread the batter into the prepared pan. Scatter the remaining 2 cups blueberries over the top, then sprinkle the crumb topping evenly over everything.
10. Bake 60-75 minutes, starting to check at 55. It is done when the top is browned, the center springs back lightly, and a tester inserted into the cakey part comes out mostly clean (blueberry juice is fine). If the top browns too fast, tent loosely with foil after about 40-45 minutes.
11. Cool completely before cutting. This cuts much more cleanly once fully cooled, and even better after a few hours.

 

Serving and make-ahead

1. Cut into squares once fully cool. For a donor-party buffet, 20-24 pieces is a good target size if the brownies are also on the table.
2. If making ahead, bake the day before, cool completely, then cover loosely. If your kitchen is warm, store covered at cool room temperature overnight or refrigerate and bring out before serving.
3. Transport the buckle in the foil pan on the sheet pan or a rigid tray so the pan does not flex and crack the crumb topping.

 

Notes

• Frozen berries: Do not thaw. Thawed berries dump extra liquid into the batter and can make the center gummy.
• Wild blueberry advantage: The small berries distribute more evenly than big cultivated blueberries, so every square gets blueberry action.
• How much from the Wyman’s bag: This recipe uses about 2 lb (roughly two-thirds of the 3 lb bag). Save the rest for oatmeal, smoothies, pancakes, or a future buckle if you become a buckle baron.
• Buttermilk substitute: If using milk plus lemon juice or vinegar, let it sit 5 minutes before adding to the batter.