Ingredients

3/4 cup (1 1/2 sticks) unsalted butter, melted, plus more for pan 

3/4 cup packed light-brown sugar 

1/4 cup granulated sugar 

1 large egg 

1/2 teaspoon salt 

1/2 teaspoon ground cinnamon 

1 cup all-purpose flour, (spooned and leveled) 

2 cups old-fashioned rolled oats (not quick-cooking) 

1 cup raisins 

Preparation

Preheat oven to 350 degrees. Butter an 8-inch square baking pan. Line bottom with parchment paper, leaving an overhang on two sides; butter paper.

In a large bowl, whisk together butter, sugars, egg, salt, and cinnamon until smooth. Add flour, oats, and raisins; fold in just until combined.

Spread batter in prepared pan, and bake until a toothpick inserted in center comes out with moist crumbs attached, 25 to 30 minutes. Cool completely in pan. Using paper overhang, lift cake onto a work surface; cut into 16 bars.