For the filling:
1/4 cup packed golden brown sugar
1/4 cup granulated sugar
2 tablespoons ground cinnamon
3 tablespoons unsalted butter
3/4 cup Grape-Nuts cereal, plus more to top
For the dough:
10 ounces (2 1/4 cups) all-purpose flour, plus more for dusting
1 tablespoon baking powder
1/2 teaspoon salt
1/4 teaspoon baking soda
1 cup cottage cheese (2% or 4%)
1/2 cup low-fat buttermilk
1 egg yolk
1/4 cup granulated sugar
1 teaspoon vanilla bean paste or pure vanilla extract
For the frosting:
2 ounces cream cheese, at room temperature
1/2 cup powdered sugar
2 tablespoons unsalted butter, at room temperature
1/4 teaspoon vanilla bean paste or pure vanilla extract
Preheat the oven to 375°F. Grease the sides and bottom of a 9- or 10-inch springform pan with cooking spray or butter.
For the filling: Combine the brown sugar, sugar, and cinnamon in a small bowl. Melt butter in a small bowl in the microwave and set aside. Measure out the Grape-Nuts in a separate bowl.
For the dough: Whisk the flour, baking powder, salt, and baking soda together in a medium mixing bowl. Combine the cottage cheese, buttermilk, egg yolk, sugar, and vanilla in the bowl of a food processor and process until smooth. Add the flour mixture to the food processor and pulse quickly, 6 to 8 times, until dough just begins to clump together; it will be very sticky and wet.
Turn the dough out onto a lightly floured work surface and gather it into a ball. Place the ball on a large baking sheet lined with parchment paper or a silicone baking mat and transfer to freezer to chill for 10 to 15 minutes.
Lightly flour the chilled dough (as well as your hands) then gently press and stretch the dough into a 12x15-inch rectangle. Using a small silicone pastry brush, brush the melted butter over dough, leaving 1/2-inch border on all sides. Sprinkle the cinnamon-sugar mixture evenly over the dough, followed by the Grape Nuts. Return the baking sheet to the freezer to chill for 10 to 15 minutes.
To make the rolls: Starting at the long side closest to you, carefully roll the dough into tight log, using the paper, not your hands, as a guide. (Think of rolling sushi!) Gently pinch the seam to seal. Slice the dough into 12 equal pieces. Place the rolls cut side up the the springform pan. (It’s okay if there are small gaps, they will expand as they cook.)
Bake the cinnamon rolls until golden and firm to the touch, 25 to 27 minutes. While the rolls are baking, make the frosting: combine the cream cheese, powdered s