1-Getting Started: First, preheat your oven to 350°F and position the rack in the center. Lightly spray a 9-inch square baking pan with nonstick spray to prevent sticking. This simple prep ensures your cake bakes evenly and releases easily.

2-Making the Brown Butter: Next, melt ¾ cup of unsalted butter in a saucepan over medium heat. Cook it, swirling occasionally, for about 5 minutes until golden brown solids form at the bottom and foam appears on top. Once done, scrape the browned bits into a mixing bowl with the hot butter to capture all that nutty flavor.

3-Making the Brown Butter: Now, add 1 cup of lightly packed light brown sugar and whisk until combined. Follow by adding 2 large eggs and 1 teaspoon of vanilla extract, whisking until smooth. Then, whisk in ⅔ cup of whole milk and ⅓ cup of sour cream to create a creamy base.

4-Combining Dry Ingredients: In a separate bowl, sift together 1 ½ cups of all-purpose flour, ½ teaspoon of coarse Kosher salt, 1 teaspoon of baking powder, ½ teaspoon of ground cinnamon, and ¼ teaspoon of ground nutmeg. This step helps avoid lumps and ensures even distribution.

5-Baking and Finishing: Add the dry ingredients to the wet mixture and whisk just until combined and mostly smooth. Pour the batter into the prepared pan and bake for 28-30 minutes, or until a tester inserted in the center comes out clean and the sides slightly pull away from the edges. Cool the cake on a rack for at least 45 minutes before serving with the prepared toffee sauce and vanilla ice cream.