Warmth oven: To 350°F (175°C). Frivolously coat an 8-inch sq. or 9-inch cake pan with butter or nonstick spray. For further safety, line it with parchment paper.

Make crumbs: Whisk butter, sugars, cinnamon, and salt collectively till evenly blended. Add flour and blend till it disappears. It’s going to be very thick; press it evenly into the underside of the bowl and set it apart.

Make cake: Beat butter with sugar till lightened and fluffy. Add egg, water or milk, bitter cream, and vanilla and beat till mixed. Sprinkle floor of batter with baking powder and salt, and beat properly to mix. Add flour and blend solely till it disappears.

Assemble: Scrape batter into ready cake pan and clean it flat. Use a spoon to loosen the crumbs from the underside of the bowl the place they’ve rested, breaking them up into large and small rubble. Sprinkle evenly over the batter.

Bake: Bake for about 30 to 35 minutes, or till a toothpick inserted into the cake slightly below the crumbs comes out batter-free. Verify in a couple of spots, in case it has baked erratically.

Cool to lukewarm, in the event you can bear it, earlier than dusting it generously with powdered sugar and chopping the cake into squares or wedges.

Do forward: This cake retains in an hermetic container at room temperature for 3 to 4 days, however I prefer it finest within the first two.