Recipe

Bright Monster Cookies

Chewy, crisp-edged monster cookies with lemon zest, vanilla, and a sneaky hit of fresh rosemary for a bright, not-too-sweet cookie that still brings the fun.

By Matt Campbell

•

4.8

A plate of colorful monster cookies with visible candy pieces and a few rosemary sprigs on a sunlit kitchen counter

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Monster cookies are usually all about cozy peanut butter, oats, and candy chaos. This version keeps the classic chewy center and crisp edges, but leans bright and herbal with lemon zest and a little rosemary. It sounds fancy, but it eats like the cookie you make when you want something fun that also makes you pause mid-bite and go, “Wait, what is that?!”

Think of it like this: peanut butter and oats give you the comfy base, lemon lifts everything, and rosemary adds that subtle, woodsy “grown-up” note that makes the chocolate and candy pop even more. No hard-to-find ingredients, no pastry chef drama, and yes, you can absolutely taste as you go.

A close-up of a monster cookie broken in half showing a chewy oat-filled center with colorful candy and chocolate chips

Why It Works

Bright flavor without being sour: Lemon zest brings fragrance and lift, not tangy juice that can mess with texture.
Herbal, not soapy: Finely chopped rosemary is used in a small amount, just enough to whisper in the background.
Chewy center, crisp edges: Oats plus a chill (optional but recommended) gives you that perfect bakery-style spread.
Classic monster cookie energy: Peanut butter, chocolate chips, and candy-coated chocolates keep it playful.

Pairs Well With

Storage Tips

Room temp: Store cookies in an airtight container for up to 4 days. Add a slice of bread to the container if you want them extra chewy. The cookies will steal moisture from the bread like tiny delicious thieves.

Freeze baked cookies: Freeze in a zip-top bag with parchment between layers for up to 2 months. Thaw at room temperature, or warm for 3 to 5 minutes in a 300°F oven to bring back the crisp edges.

Freeze dough balls: Scoop, freeze on a sheet pan, then bag. Bake from frozen, adding 1 to 3 minutes to bake time.

Common Questions

Will the rosemary taste like a holiday roast?

Nope, not if you keep it small and finely chopped. It reads more like “fresh, piney, citrus-friendly” than savory. If you are rosemary-shy, start with half the amount and work up next time.

Can I skip the peanut butter?

Monster cookies really want that peanut butter base, but you can swap in almond butter or sunflower seed butter 1:1. Sunflower butter can turn baked goods a little green because of a natural reaction with baking soda. Totally safe, slightly weird, kind of fun. (If you ever want to reduce the green, a tiny bit of acid can help, but this recipe intentionally keeps extra liquid out.)

Do I need to chill the dough?

Not required, but chilling for 30 minutes helps control spread and gives the oats time to hydrate for a thicker, chewier cookie. If your kitchen is warm or your butter is very soft, chilling is a good idea.

Can I use quick oats?

Old-fashioned rolled oats give the best chew. Quick oats work in a pinch, but the cookies will be a little more uniform and less hearty.

Why no lemon juice?

Zest gives bright citrus aroma without adding extra liquid or acidity that can change the cookie’s texture. If you want more lemon, add a tiny drop of lemon extract or bump up the zest.

Can I bake two pans at once?

Yep. Bake on the upper and lower racks, then swap racks and rotate the pans halfway through so everything bakes evenly.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

Large mixing bowl
Whisk and flexible spatula
Measuring cups and spoons
Microplane or fine grater (for lemon zest)
Chef’s knife (for chopping rosemary)
Cookie scoop (optional, but makes life easier)
Sheet pans
Parchment paper
Wire cooling rack

I started messing with these after one of those nights where you want a cookie, but not a sugar-bomb cookie. I had rosemary on the counter from dinner, a lemon that needed to be used, and a bag of candy-coated chocolates that was absolutely not going to survive the week. The first batch tasted like a normal monster cookie that had been to therapy and came back with better boundaries. Brighter, calmer, still a little chaotic. Now it’s the cookie I bake when I want something familiar with a twist that makes people ask for the recipe.

Bright Monster Cookies

(4.8 Reviews)

Prep Time 15 minutes

Cook Time 12 minutes

Total Time 27 minutes

Servings 25 cookies

Ingredients

1/2 cup (113 g) unsalted butter, melted, then cooled until just warm (not hot), 5 to 10 minutes
1/2 cup (125 g) creamy peanut butter
3/4 cup (150 g) light brown sugar, packed
1/4 cup (50 g) granulated sugar
1 large egg, room temperature
2 tsp vanilla extract
Zest of 1 large lemon (about 1 to 2 tsp)
1 tsp fresh rosemary, very finely chopped
1 cup (125 g) all-purpose flour
1 tsp baking soda
1/2 tsp kosher salt
2 cups (180 g) old-fashioned rolled oats
3/4 cup (135 g) candy-coated chocolates (like M&M’s), plus extra for topping
1/2 cup (85 g) semisweet chocolate chips
Optional: flaky salt for finishing

Note: If your rosemary is super punchy, start with 1/2 tsp. You can always go bigger next batch.

Instructions

Heat the oven. Preheat to 350°F (175°C). Line two sheet pans with parchment. If baking both at once, set racks to the upper and lower positions.
Mix the wet base. In a large bowl, whisk together melted butter (cooled until just warm), peanut butter, brown sugar, and granulated sugar until glossy and smooth.
Add the flavor. Whisk in the egg, vanilla, lemon zest, and finely chopped rosemary. Whisk 10 to 15 seconds, or until it smells like you are about to do something smart with a lemon.
Add dry ingredients. Add flour, baking soda, and salt. Stir with a spatula just until you stop seeing streaks of flour. (If you are a “no clumps ever” person, whisk the dry ingredients together in a small bowl first, then add.)
Bring the monster energy. Fold in oats, candy-coated chocolates, and chocolate chips. The dough will be thick and studded, like it is carrying groceries for the whole neighborhood.
Optional chill. If you have time, chill the dough for 30 minutes for a slightly thicker cookie and more controlled spread.
Scoop and top. Scoop 2-tablespoon portions (about 40 g each) onto sheet pans, leaving space to spread. Press a few extra candy pieces on top for that bakery look.
Bake. Bake for 10 to 12 minutes, until edges look set and lightly golden but centers still look a little soft. If baking two pans at once, swap racks and rotate pans at the halfway mark.
Cool correctly. Let cookies cool on the pan for 10 minutes (this finishes the set), then transfer to a rack. If you want, hit them with a tiny pinch of flaky salt while warm.

Matt’s tiny save: If your cookies spread too much, your butter was probably too hot, or your dough was too warm. Next round, let the butter cool longer, or chill the dough. If they do not spread much, flatten the dough balls slightly before baking.

Nutrition information is estimated.

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