Line a section of counter next to the stove with waxed paper
Combine sugar, butter, milk, cocoa powder, salt and (if you're using it) espresso powder in a medium saucepan, place over medium high heat.
400 g sugar, 112 g butter, 120 ml milk, 24 g cocoa powder, 2 g salt, 1/4 tsp espresso powder
Bring to a rolling boil and continue boiling for 2 - 2 1/2 minutes (use a timer).
Remove from the heat, immediately stir in vanilla and peanut butter until combined.
64 g peanut butter, 8 ml vanilla
Add oats, stir until well combined. All of the oats should be fully coated in the syrup.
240 g quick oats
Quickly drop mounds of the mixture by tablespoon or small cookie scoop (#40) onto wax paper, about 1 inch apart.
Allow to cool undisturbed until fully set and easily removed from the wax paper (about 15-20 minutes).
Notes
Mom’s recipe calls for a 1–1½ minute boil, but I use 2 - 2 1/2 minutes because my kitchen is at a higher elevation and the syrup takes a bit longer to reach the right consistency. If you want to be precise, use a candy thermometer and pull the mixture off the heat at 230–235°F.
This recipe is wonderfully forgiving when it comes to the cocoa and peanut butter ratios. I increase both in my version for a deeper, more intense flavor, but you can go the opposite direction or even skip the cocoa entirely (or swap in peanut butter powder) for a pure peanut butter experience. If you’d like to experiment, adjust in small increments—about 1 tablespoon at a time—until you land on your perfect balance.