Blueberry Buckle with Jaca
A blueberry buckle is the ultimate summer coffee cake — a tender, lemon-kissed cake studded with juicy fresh blueberries and crowned with a sweet, buttery cinnamon streusel that crackles as it bakes. As the cake rises around the berries in the oven it "buckles," giving this old-fashioned favorite its name. It is the perfect thing to slice warm alongside a morning coffee or serve à la mode for dessert, and it is a beautiful place to show off our Jaca swap. We replace every bit of the conventional sugar with Jaca (100% pure allulose) at double the amount: 1 1/2 cups of granular Jaca in the cake in place of 3/4 cup of the sugar we grew up with, plus 1 cup of granular Jaca in the streusel topping in place of 1/4 cup brown and 1/4 cup granulated sugar — so you get the same tender crumb and crackly, buttery topping with no added sugar and no aftertaste. Because allulose is only about 70% as sweet as traditional sugar, doubling it lands the sweetness right where it should be. It comes together in about 15 minutes and bakes in a single 8x8 pan — makes 9 generous squares. Adapted from Spend With Pennies. This is a Jaca-adjusted healthier version.
Ingredients
- 1 1/2 cups Jaca (allulose), granular (for the cake — replaces 3/4 cup granulated sugar at the 2x ratio)
- 1/4 cup butter, softened
- 1 large egg
- 2 teaspoons lemon zest (about 1 lemon)
- 1 1/2 cups all-purpose flour
- 2 teaspoons baking powder
- 1/2 teaspoon salt
- 1/2 cup milk
- 1 tablespoon all-purpose flour (for tossing the blueberries)
- 1 1/2 cups fresh blueberries
- 5 tablespoons butter, cold (for the topping — 1/4 cup plus 1 tablespoon)
- 1/2 cup Jaca (allulose), granular (for the topping — replaces 1/4 cup brown sugar at the 2x ratio)
- 1/2 cup Jaca (allulose), granular (for the topping — replaces 1/4 cup granulated sugar at the 2x ratio)
- 1/3 cup all-purpose flour (for the topping)
- 1/2 teaspoon cinnamon (for the topping)
Sweetener Used
2 1/2 cups granular Jaca total (1 1/2 cups cake + 1 cup topping) Allulose
Replaces: 1 1/4 cups sugar (3/4 cup granulated in the cake, plus 1/4 cup brown and 1/4 cup granulated in the topping)
Instructions
- 1
Preheat the oven to 350°F and grease an 8x8-inch baking pan.
- 2
In a large bowl, cream together the 1 1/2 cups granular Jaca, softened butter, egg, and lemon zest until light and fluffy. The Jaca steps in for the sugar here at double the amount, so you get the same tender sweetness with no added sugar.
- 3
In a separate bowl, whisk together the 1 1/2 cups flour, baking powder, and salt. Add to the Jaca mixture in batches, alternating with the milk, and mix just until combined — do not overmix.
- 4
Toss the blueberries with the 1 tablespoon flour to coat (this keeps them evenly distributed), then gently fold them into the batter. Spread the batter evenly into the prepared pan.
- 5
Make the streusel: in a small bowl, combine the cold butter, 1/2 cup granular Jaca (for the brown sugar), 1/2 cup granular Jaca (for the granulated sugar), 1/3 cup flour, and cinnamon. Cut or rub together with a fork or your fingertips until the mixture is crumbly, then sprinkle it evenly over the batter.
- 6
Bake for 40 to 45 minutes, until the topping is golden and a toothpick inserted into the center (avoiding the berries) comes out clean. Cool for at least 15 minutes before slicing. Serve warm or at room temperature.
Pro Tips
- Jaca is about 70% as sweet as conventional sugar, which is exactly why we double it — you get the same tender crumb and buttery streusel with no added sugar and no aftertaste.
- Toss the blueberries in a tablespoon of flour before folding them in — it keeps them suspended in the batter instead of sinking to the bottom.
- Fresh blueberries are best, but frozen work too — no need to thaw; just add a few extra minutes of baking time (the batter may tint blue, but it will still taste amazing).
- The lemon zest is the secret weapon — it brightens the whole cake and pairs perfectly with the blueberries. Zest only the yellow skin, not the bitter white pith underneath.
- For a deeper brown-sugar note in the streusel, stir 1/2 teaspoon of molasses into the granular Jaca before cutting in the butter.
- Serve warm with a scoop of ice cream or a dollop of whipped cream, or enjoy at room temperature with coffee. It also freezes beautifully once fully cooled.