Preheat the oven to 350°F (175°C). Line a pan with parchment paper, covering the bottom and sides.

In a wide saucepan over low heat, melt the butter with the sugar, date syrup, and salt, stirring constantly. Add the pecans and mix well until the sugar dissolves. Remove from heat and pour the topping into the lined pan, spreading it evenly.

In a mixer bowl, combine eggs, sugar, oil, milk, sour cream, flour, baking powder, baking soda, and a pinch of salt. Mix until just combined and smooth.

Carefully pour the batter over the topping in the pan and spread it evenly. Bake for 40-45 minutes or until the top is golden. Remove from the oven and let it sit for 10-15 minutes.

Place a serving plate over the pan, invert the cake onto the plate, carefully lift the pan off, and serve.