Sticky Toffee Date Cake

Beat brown sugar, baking powder, cinnamon, salt, baking soda, and 2 cups flour in the large bowl of a stand mixer fitted with the paddle attachment on low speed until combined (or use a hand mixer and large bowl). Add butter (make sure it’s at room temperature) and beat on medium-low speed until mixture resembles coarse sand. Add sour cream and vanilla and continue to beat, increasing speed from medium-low to medium as the ingredients begin to incorporate, until batter is thick and smooth, about 1 minute. Scrape down sides of bowl. Reduce mixer speed to medium-low, add 1 egg, then increase speed to medium and beat 30 seconds. Repeat with remaining 2 eggs, reducing speed to medium-low after each addition, then increasing speed to medium-high and beating for 30 seconds (if you beat on medium-high speed from the get-go, you risk losing some of the batter; this ensures nothing flies out of the bowl). Scrape down sides of bowl again. Reduce speed to low, add dates, and beat until incorporated, about 30 seconds longer.