Cinnamon Sugar Monster Cookie Bars

Featured in: Cinnamon Desserts

Enjoy chewy, buttery bars loaded with chocolate candies and oats, finished with a cinnamon-sugar topping. These bars blend soft texture with a sweet crunch, creating a tempting treat ideal for sharing or enjoying anytime. Baked in a single pan and sliced into squares, they're easy to prepare and serve. The mix of semisweet chocolate chips and colorful candies adds richness and visual appeal. Each bite offers those familiar monster cookie flavors with a twist from aromatic cinnamon. Pair them with milk or coffee for an irresistible snack or dessert option. Suitable for vegetarians and quick to make, they're a crowd-pleaser on any sweet occasion.

Updated on Thu, 30 Oct 2025 16:23:00 GMT
Chewy cinnamon sugar monster cookie bars topped with colorful chocolate candies and sprinkles.  Pin
Chewy cinnamon sugar monster cookie bars topped with colorful chocolate candies and sprinkles. | cinnamonnest.com

Chewy, buttery cookie bars packed with oats, chocolate candies, and a delightful cinnamon-sugar crunch—perfect for sharing or indulging any time.

I first baked these cinnamon sugar monster cookie bars for a weekend get-together, and they were devoured within minutes. Everyone loved the buttery base, the bright chocolate candies, and the extra kick from the cinnamon sugar crust.

Ingredients

  • Unsalted butter: 1 cup (225 g), softened
  • Brown sugar: 1 cup (200 g), packed
  • Granulated sugar: 1/2 cup (100 g)
  • Large eggs: 2
  • Vanilla extract: 2 tsp
  • All-purpose flour: 1 3/4 cups (220 g)
  • Old-fashioned rolled oats: 1 1/2 cups (120 g)
  • Baking soda: 1 tsp
  • Baking powder: 1/2 tsp
  • Salt: 1/2 tsp
  • Ground cinnamon: 1 tsp
  • Chocolate candies (such as M&Ms): 1 cup (180 g)
  • Semisweet chocolate chips: 1 cup (170 g)
  • Granulated sugar (topping): 2 tbsp
  • Ground cinnamon (topping): 1 1/2 tsp

Instructions

Prepare pan:
Preheat oven to 350°F (175°C). Line a 9x13-inch (23x33 cm) baking pan with parchment paper, leaving an overhang for easy removal.
Cream butter and sugars:
In a large bowl, cream together softened butter, brown sugar, and granulated sugar until light and fluffy.
Add eggs and vanilla:
Beat in eggs one at a time, then mix in vanilla extract.
Combine dry ingredients:
In a separate bowl, whisk together flour, oats, baking soda, baking powder, salt, and cinnamon.
Mix wet and dry:
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Add chocolate:
Fold in chocolate candies and chocolate chips.
Spread dough:
Spread the dough evenly into the prepared pan.
Top with cinnamon sugar:
Mix the cinnamon sugar topping ingredients in a small bowl, then sprinkle evenly over the top of the dough.
Bake:
Bake for 23–27 minutes, until the edges are golden and a toothpick inserted in the center comes out with moist crumbs.
Cool and cut:
Allow to cool completely in the pan before lifting out and cutting into bars.
Warm, golden cookie bars filled with oats and chocolate, topped with cinnamon sugar.  Pin
Warm, golden cookie bars filled with oats and chocolate, topped with cinnamon sugar. | cinnamonnest.com

Our kids love helping sprinkle the cinnamon sugar on top, and sharing these bars has become a Saturday tradition in our home.

Required Tools

Mixing bowls, parchment paper, 9x13-inch baking pan, electric mixer or sturdy whisk, measuring cups and spoons, spatula

Nutritional Information

Each bar contains approximately 280 calories, 13 g total fat, 38 g carbohydrates, and 3 g protein

Notes

For extra color, mix regular and mini chocolate candies. Substitute with peanut butter chips or butterscotch chips for a twist. Serve with milk or coffee for a classic pairing.

Indulgent cinnamon sugar monster cookie bars ready to serve with a glass of milk. Pin
Indulgent cinnamon sugar monster cookie bars ready to serve with a glass of milk. | cinnamonnest.com

Try these cookie bars warm or cooled for an irresistible dessert everyone will request again.

Recipe FAQ

Can I use quick oats instead of old-fashioned oats?

Quick oats can be used but will yield a slightly softer texture than rolled oats. Old-fashioned oats provide more chewiness.

What other mix-ins work well?

Try adding peanut butter chips, butterscotch chips, nuts, or white chocolate chips for variety and extra flavor.

How do I know the bars are done baking?

Check for golden edges and a toothpick inserted in the center that comes out with moist crumbs, not wet batter.

Can I freeze the bars?

Yes, cool completely, cut into portions, and freeze in an airtight container for up to 2 months for later enjoyment.

What is the best way to store these bars?

Store in an airtight container at room temperature for up to 5 days to maintain freshness and texture.

Cinnamon Sugar Monster Cookie Bars

Chewy, buttery cookie bars loaded with oats, chocolate candies, and a crunchy cinnamon-sugar finish.

Prep duration
20 min
Cooking duration
25 min
Total duration
45 min


Difficulty Easy

Origin American

Yield 16 Servings

Dietary requirements Vegetarian

Ingredients

Cookie Dough

01 1 cup unsalted butter, softened
02 1 cup brown sugar, packed
03 1/2 cup granulated sugar
04 2 large eggs
05 2 teaspoons vanilla extract
06 1 3/4 cups all-purpose flour
07 1 1/2 cups old-fashioned rolled oats
08 1 teaspoon baking soda
09 1/2 teaspoon baking powder
10 1/2 teaspoon salt
11 1 teaspoon ground cinnamon
12 1 cup chocolate candies (such as M&Ms)
13 1 cup semisweet chocolate chips

Cinnamon Sugar Topping

01 2 tablespoons granulated sugar
02 1 1/2 teaspoons ground cinnamon

Directions

Step 01

Prepare Pan: Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving overhang for easy removal.

Step 02

Cream Butter and Sugars: In a large bowl, beat together softened butter, brown sugar, and granulated sugar until light and fluffy using an electric mixer or sturdy whisk.

Step 03

Add Eggs and Vanilla: Beat in eggs one at a time. Mix in vanilla extract until well combined.

Step 04

Combine Dry Ingredients: In a separate bowl, whisk together flour, oats, baking soda, baking powder, salt, and cinnamon.

Step 05

Mix Wet and Dry Ingredients: Gradually add the dry ingredient mixture to the wet mixture, mixing until just combined.

Step 06

Incorporate Add-ins: Fold in chocolate candies and semisweet chocolate chips.

Step 07

Spread Dough: Evenly spread the dough into the prepared baking pan.

Step 08

Prepare Topping: Combine granulated sugar and ground cinnamon for the topping in a small bowl.

Step 09

Add Topping: Sprinkle the cinnamon sugar topping evenly over the dough.

Step 10

Bake: Bake for 23 to 27 minutes, until edges are golden and a toothpick inserted in the center comes out with moist crumbs.

Step 11

Cool and Cut: Allow to cool completely in the pan before lifting out and cutting into bars.

Necessary tools

  • 9x13-inch baking pan
  • Parchment paper
  • Mixing bowls
  • Electric mixer or sturdy whisk
  • Measuring cups and spoons
  • Spatula

Allergy information

Review ingredients carefully for potential allergens and consult with a healthcare provider if you're uncertain.
  • Contains wheat (gluten), eggs, dairy, and soy from chocolate candies and chips.
  • Chocolate candies may contain peanuts or tree nuts; check labels for specific allergens.

Nutritional information (per serving)

These values are approximate guidelines only and shouldn't replace professional medical advice.
  • Calories: 280
  • Fat: 13 g
  • Carbs: 38 g
  • Protein: 3 g