Active Time

　　25 min

　　Total Time

　　3 1/2 hr (includes cooling)

　　

Ingredients

Makes 1 (8 1/2- by 4 1/2-inch) loaf

　　2 1/4 sticks unsalted butter

　　2 cups sifted cake flour (not self-rising; sift before measuring)

　　1 teaspoon baking powder

　　1/2 teaspoon salt

　　1/2 cup packed light brown sugar

　　1/2 cup granulated sugar

　　4 large eggs

　　1/2 teaspoon pure vanilla extract

　　

Step 1

Preheat oven to 325°F with rack in middle. Butter and lightly flour an 8 1/2-by 4 1/2-inch loaf pan.

　　

Step 2

Heat butter in a 10-inch heavy skillet over medium heat until milk solids on bottom are a dark chocolate brown. Transfer to a shallow bowl and chill in freezer until just congealed, about 15 minutes.

　　

Step 3

Whisk together flour, baking powder, and salt.

　　

Step 4

Beat together brown butter and sugars with an electric mixer until fluffy, about 2 minutes. Add eggs 1 at a time, beating well after each addition. Beat in vanilla.

　　

Step 5

At low speed, mix in flour mixture until just incorporated.

　　

Step 6

Transfer batter to pan, smoothing top, then rap pan on counter to settle batter. Bake until golden-brown and a wooden pick inserted into center comes out clean, 1 to 1 1/4 hours. Cool in pan 30 minutes, then invert cake onto a rack and cool completely, right side up, 1 hour.