Make the pecan topping:

1. Preheat the oven to 350°F (175°C). Grease a 9-inch round cake pan with butter or cooking spray.
2. In a small saucepan, combine 1/2 cup packed brown sugar, 1 stick of unsalted butter, 1/4 cup honey, and 1/8 teaspoon kosher salt. Cook over medium-low heat, stirring frequently, until the butter is melted and the sugar is dissolved.
3. Stir in 1 1/4 cups of coarsely chopped pecans. Pour the mixture into the prepared cake pan and spread it into an even layer.

Make the cake:

1. In a medium bowl, whisk together 1 1/2 cups all-purpose flour, 1 1/2 teaspoons baking powder, and 1/2 teaspoon baking soda.
2. In a large bowl, whisk together 3/4 cup sour cream, 2 eggs, 3/4 cup granulated sugar, 1/2 cup neutral oil, 1/4 cup water, 1 teaspoon vanilla extract, and 1/2 teaspoon kosher salt until smooth.
3. Gradually add the flour mixture to the wet ingredients, stirring until just combined (do not overmix).
4. In the now-empty flour bowl, mix 1/4 cup packed brown sugar and 2 teaspoons ground cinnamon.

Assemble and bake:

1. Dollop half of the cake batter (about 1 1/2 cups) over the pecan topping in the pan. Spread it into an even layer.
2. Sprinkle the cinnamon-sugar mixture evenly over the batter.
3. Dollop the remaining batter on top and carefully spread it into an even layer, covering the cinnamon-sugar mixture.
4. Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean. If the cake browns too quickly, tent it with aluminum foil after 30 minutes.

Cool and serve:

1. Let the cake cool in the pan for 10-15 minutes. Run a knife around the edges to loosen it, then invert it onto a serving plate.
2. Sprinkle with flaky salt if desired. Let it cool to room temperature.
3. Serve with a scoop of vanilla ice cream for an extra indulgent treat!