4.5 from 129 votes
Monster Cookie Bars
Monster Cookie Bars bring together peanut butter, oats, and chocolate chips into a dense, chewy bar with a crisp-edged finish. The combination of brown sugar and peanut butter creates a rich, sweet base, while old-fashioned oats add texture. Baking the batter pressed into a pan results in bars with slightly undercooked centers topped with colorful M&M's for added chew and visual appeal. These bars are convenient to cut and serve, making them practical for snacks or casual desserts.
Prep Time
10 mins
Cook Time
15 mins
Total Time
25 mins
Servings:
24
bars
Calories:
224 kcal
Course:
Snacks
Cuisine:
American
Ingredients
- ½ cup butter at room temperature, unsalted
- 1 cup light brown sugar
- ½ cup peanut butter creamy
- 1 egg
- 2 teaspoons vanilla extract
- ¾ cup all-purpose flour
- 1 teaspoon baking soda
- 1 teaspoon cornstarch
- ¼ teaspoon baking powder
- ¼ teaspoon salt
- 1½ cups old-fashioned oats
- 1 cup semisweet chocolate chips
- 1 cup M&M's additional for top of bars
Instructions
- Preheat the oven to 350 degrees F. Grease a 9x13-inch paking pan and line with parchment paper so that it hangs over two sides.
- In a small bowl, whisk together the flour, baking soda, cornstarch, baking powder and salt.
- In a large bowl, cream together the butter, brown sugar, and peanut butter on medium speed until light and fluffy, about 3 minutes. Add the egg and vanilla, scraping down the sides of the bowl as needed. Reduce the mixer speed to low and slowly add the flour mixture to the wet ingredients and mix until just combined. Using a rubber spatula, stir in the oats, chocolate chips and M&M's by hand.
- Turn the dough out into the prepared baking sheet and press/spread into an even layer. Press additional M&M's onto the top of the dough. Bake for 15 to 17 minutes, until the edges are set and lightly browned and the top still looks slightly undercooked. Remove from the oven and cool completely before cutting into bars. The bars should be stored in an airtight container at room temperature for up to 4 days.
Cup of Yum
Notes
- Use parchment paper hanging over sides of the baking pan for easy removal and cutting of bars.
- Let bars cool completely before cutting to ensure clean slices and proper texture.
- Store finished bars in an airtight container at room temperature to maintain freshness.
- Double-check measure of baking powder and cornstarch for balanced texture in the crumb.
Nutrition Information
Calories
224kcal
(11%)
Carbohydrates
26g
(9%)
Protein
3g
(6%)
Fat
11g
(17%)
Saturated Fat
6g
(30%)
Cholesterol
18mg
(6%)
Sodium
107mg
(4%)
Potassium
118mg
(3%)
Fiber
1g
(4%)
Sugar
17g
(34%)
Vitamin A
150IU
(3%)
Vitamin C
0.1mg
(0%)
Calcium
32mg
(3%)
Iron
1.2mg
(7%)
Nutrition Facts
Serving: 24 bars
Amount Per Serving
Calories 224
% Daily Value*
| Calories | 224kcal | 11% |
| Carbohydrates | 26g | 9% |
| Protein | 3g | 6% |
| Fat | 11g | 17% |
| Saturated Fat | 6g | 30% |
| Cholesterol | 18mg | 6% |
| Sodium | 107mg | 4% |
| Potassium | 118mg | 3% |
| Fiber | 1g | 4% |
| Sugar | 17g | 34% |
| Vitamin A | 150IU | 3% |
| Vitamin C | 0.1mg | 0% |
| Calcium | 32mg | 3% |
| Iron | 1.2mg | 7% |
* Percent Daily Values are based on a 2,000 calorie diet.