Quick Sticky Biscuits

In a saucepan over low heat, warm the brown sugar, corn syrup, and butter until the butter melts.
Increase the heat to medium-high and bring to a gentle boil. Cook, uncovered, until the mixture thickens, 3 to 5 minutes. Stir in the chopped nuts. Pour the mixture into the prepared baking dish and spread evenly.

Preheat the oven to 425°F (220°C) and adjust the oven rack to the middle position. Generously coat a 9-by-13-inch baking dish with butter or nonstick cooking spray.
In a large bowl, sift together the flour, baking powder, baking soda, and salt.
Using a pastry cutter, cut the butter into the flour mixture. Blend until most of the mixture looks like coarse crumbs, with some of the bits of butter the size of small peas.
Make a shallow well in the center of the flour mixture and pour in 1 1/2 cups of the cold buttermilk. Use a fork to blend the buttermilk into the flour to create a soft dough. If the dough seems too dry, add some or all of the remaining 1/2 cup buttermilk.
Turn the dough out onto a lightly floured work surface and knead a few times until it comes together. Pat the dough into a 3/4-inch-thick rectangle. Use a chef's knife to cut the dough into 12 square biscuits.

Brush the tops of the biscuits with some of the melted butter and sprinkle with some of the cinnamon sugar. Place the biscuits, evenly spaced, cinnamon-sugar side down, into the pecan syrup-lined pan. Brush the tops of the biscuits with more melted butter and sprinkle with a little more cinnamon-sugar.
Bake the biscuits until golden brown, puffy, and bubbling, 15 to 20 minutes.
Let the biscuits cool slightly in the baking dish.
Line a rimmed baking sheet with parchment paper. Invert the baking sheet onto the baking dish and then flip everything over. Slowly remove the dish and let the sauce fall around the biscuits. Use a small spatula to scrape any sauce that clings to the baking dish onto the biscuits. Serve warm.