- 8 ounces sliced bacon, cut into 1/4-inch squares
- 1 cup (packed) dark brown sugar
- 1/2 cup (1 stick) unsalted butter, room temperature
- 1/2 teaspoon vanilla extract
Line 2 baking sheets with parchment paper. Cook bacon in a large skillet over medium-low heat, stirring occasionally, until deep golden brown and crisp. Using a slotted spoon, transfer bacon to paper towels.
Whisk flour and next 3 ingredients in a medium bowl. Using an electric mixer, beat both sugars and butter in a large bowl, occasionally scraping down sides, until well blended, 2–3 minutes. Add eggs one at a time, mixing well between additions. Add vanilla; mix on medium speed until pale and fluffy, 4–5 minutes. Mix in dry ingredients.
Fold bacon, oats, and raisins into batter and stir until evenly incorporated (dough will be sticky; chill briefly for easier handling, if desired). Using a 2-oz. ice cream scoop or 1/4-cup measure and forming dough into balls, scoop batter onto prepared sheets, spaced at least 3 inches apart. Chill dough for 1 hour or cover and chill overnight.
Arrange racks in upper and lower thirds of oven; preheat to 375°. Bake cookies, rotating pans halfway through, until edges are light golden brown and centers are still slightly soft, 20–22 minutes. Let cool on baking sheets for 10 minutes. Transfer to a wire rack; let cool completely. do ahead: Can be made 3 days ahead. Store airtight at room temperature.