Preheat your oven to 350ºF (177ºC) and bring your butter, sour cream, cream cheese and egg to room temperature.I place my egg in a bowl of warm water for a few minutes and leave out the butter and sour cream for a few hours. If needed, I microwave them for a few seconds until they're room temperature or a little warm. Place room temperature butter and granulated sugar into the bowl of your stand mixer with the whisk attachment. (Or a large bowl if you’re using a hand mixer.) Mix on medium/high and cream together until light and fluffy, about 2-3 minutes.Make sure it’s fully creamed, if it’s not light and fluffy then your cake could collapse.
Add in your room temperature egg, room temperature sour cream and vanilla. Mix until combined. Your batter should look cohesive at this point. If it has chunks of cold butter in there, one of your ingredients was too cold.
Add in the flour, baking soda, baking powder and salt. Mix on low until just combined. Don’t over mix. (If your flour is really lumpy, sift these dry ingredients before adding them into the mixer.) The batter will be thick.
Grease an 8”x4” loaf pan with pan release on the bottom and up the sides. I recommend using cake goop! Or you can line the bottom and sides with parchment paper to easily flip it out later.
Place half of the batter into the greased loaf pan and smooth it out. Sprinkle the cinnamon sugar filling on top until it’s completely covered. (Optional: swirl if desired.) Then place the rest of the batter on top and smooth it out with a spatula.
Sprinkle the thick crumbs evenly on top, covering the surface of the batter.
Bake at 350ºF for 40-50 minutes, rotating halfway through for even baking. When a toothpick comes out clean from the center, it’s done!
Make the cream cheese glaze while your cake is baking, directions below.
Once finished baking, rest the loaf at room temperature until the pan is completely cool, about 2 hours. Do NOT flip your cake out while it’s warm, it could collapse.
Loosen the edges with a knife, place a piece of plastic wrap on top of the cake and flip upside down to remove it from the pan. Place on top of a plate or serving tray.