Why It Works
- Using milk instead of butter gives these cookies more lactose, which develops a toasty, toffee-like flavor as it cooks.
- A blend of cocoa powder and dark chocolate amps up the flavor.
- Peanut butter gives the cookies a creamy consistency and a salty/sweet flavor.
- Combining rolled and instant oats provides a good balance of thickness and chew.
Believe it or not, these peculiarly American treats are a type of creamy peanut butter fudge masquerading as a chewy oatmeal cookie. Don't let the idea of fudge throw you off: As long as you're armed with a digital thermometer, this recipe couldn't be simpler, or more rewarding.
- 7 ounces plain or lightly toasted sugar (about 1 cup; 200g)
- 6 ounces milk (about 3/4 cup; 170g); any percentage will do
- 1/2 ounce Dutched cocoa powder (about 2 tablespoons; 15g), such as Cacao Barry Extra Brute
- 1/4 teaspoon (1g) Diamond Crystal kosher salt; for table salt, use about half as much by volume or use the same weight
- 1 ounce dark chocolate, about 72% (about 2 tablespoons; 30g), melted
- 4 ounces creamy peanut butter (shy 1/2 cup; 110g); commercial styles work best
- 1 teaspoon vanilla extract
- 2 ounces instant oatmeal (shy 2/3 cup; 55g); see note
- 1 ounce old-fashioned rolled oats (heaping 1/4 cup); see note
Whisk sugar, milk, cocoa, and salt together in a 3-quart stainless steel saucier. Bring to a boil over medium heat (this should take about 5 minutes), then clip-on a digital thermometer and continue cooking until mixture is bubbly, thick, and exactly 230°F (110°C), about 6 minutes longer. For best results, avoid handheld thermometers, which may not perform well due to unsteady placement during long-term projects such as candy.
Off heat, whisk in melted chocolate, peanut butter, and vanilla extract. Using a flexible, heat-resistant spatula, fold in both types of oats. Stir just until mixture begins to thicken, then drop onto a parchment-lined half sheet pan, using a pair of metal spoons. Cool until cookies are firm and dry to the touch, about 25 minutes, and transfer to an airtight container. Store about 2 weeks at room temperature or up to 1 month in the fridge.
I love these cookies best with a blend of instant and old-fashioned oats, but it's fine to use just one or the other. Instant oats will produce a more homogeneous, cookie-like texture, while rolled oats will give them a heartier chew. You'll still be using a total of 3 ounces (85g) either way, but the volume will differ. For instant oats, use about 3/4 cup; for old-fashioned rolled oats (not thick-cut), use about 1 cup.