Cooking Instructions:

• In a mixing bowl, combine the melted butter, granulated sugar, brown sugar, flour, instant espresso powder, ground cinnamon, and a pinch of sea salt. Use a fork or your fingers to mix until the mixture resembles coarse crumbs. Set aside while you prepare the cake batter.
• In a large bowl, cream together the room-temperature unsalted butter and granulated sugar until the mixture is light and fluffy. This should take about 3-5 minutes. Add the egg and vanilla extract, mixing until fully incorporated.
• Add the full-fat sour cream to the mixture, blending well. Ensure everything is nicely mixed before moving on to the dry ingredients.
• In a separate bowl, whisk together the all-purpose flour, baking soda, baking powder, and fine sea salt. Gradually add these dry ingredients to the wet mixture, stirring until just combined. Be careful not to overmix; a few lumps are okay.
• Preheat your oven to 350°F (175°C). Grease your baking pan and pour half of the cake batter into the prepared pan, spreading it evenly. Sprinkle half of the crumb topping over the batter. Pour the remaining batter on top of the crumbs, smoothing it out, and then finish with the rest of the crumb topping.
• Place the cake in the preheated oven and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Keep an eye on it during the last few minutes to prevent over-baking.
• Once baked, remove the cake from the oven and let it cool in the pan for about 10 minutes. Then, transfer it to a cooling rack to cool completely. While it cools, prepare the espresso glaze by whisking together the sifted confectioner’s sugar, brewed espresso (or dissolved instant espresso), and a pinch of fine sea salt until smooth. Drizzle over the cooled cake.