Chewy Monster Cookie Bars with M&Ms and Peanut Butter

Monster Cookie Bars are an ideal Halloween treat. These homemade oatmeal bars are lighter than traditional cookies yet still indulgent—packed with dark chocolate chips and dye-free candy-coated chocolate pieces. This peanut-free version uses a sunflower seed butter swap that keeps the bars allergy-friendly without sacrificing flavor.

Delicious Peanut-Free Monster Cookie Bars

These Monster Cookie Bars are a family favorite. They deliver the familiar fun of classic monster cookies—colourful candy pieces, chewy oats and chocolate—while using a sunflower seed butter in place of peanut butter to keep the bars nut-free and allergy-conscious. They come together quickly and make a great seasonal bake for Halloween parties, school treats, or lunchbox surprises.

Ingredients you’ll need:

• 1/2 cup sunflower seed butter (No Sugar Added preferred)
• 1/4 cup coconut oil
• 1/4 cup maple syrup
• 1 large egg (or egg replacer for vegan)
• 1/4 teaspoon sea salt
• 1 1/2 cups rolled oats (use certified gluten-free oats if needed)
• 1/2 cup brown rice crisp cereal
• 1/4 cup unsweetened coconut flakes or shredded coconut
• 1/2 cup dark chocolate chips
• 1/2 cup dye-free candy coated chocolate pieces (or your preferred topping)

How to Make Chewy Monster Cookie Bars

These bars are straightforward to prepare. The wet ingredients bind the oats and cereal into a chewy, slightly crunchy bar that keeps well in the fridge or freezer.

Step 1: Preheat the oven to 350°F (175°C).

Step 2: In a medium bowl, whisk together the sunflower seed butter, coconut oil, maple syrup, egg, and sea salt until smooth and creamy.

Step 3: Add the rolled oats, brown rice crisp cereal, and coconut to the wet mixture. Stir until the dry ingredients are fully coated and evenly distributed.

Step 4: Fold in the dark chocolate chips so they are dispersed throughout the dough.

Step 5: Press the mixture firmly into a parchment-lined or lightly greased baking dish, creating an even layer.

Step 6: Scatter the candy-coated chocolate pieces across the top and press them gently into the dough so they stay put during baking.

Step 7: Bake at 350°F for 16–18 minutes, until the edges begin to turn golden. Remove from the oven and allow to cool completely before slicing. For cleaner cuts, chill the pan in the refrigerator before slicing into bars. Store in an airtight container in the refrigerator or freeze for longer shelf life.

Variations for Making the Best Oatmeal Bar Cookies

These bars are easy to adapt:

• Skip the candy: Replace candy pieces with pumpkin seeds, dried cranberries, or chopped dried fruit for a naturally colorful option.
• Vegan option: Replace the egg with a plant-based egg replacer or a flax egg (1 tbsp ground flax + 3 tbsp water, let sit 5 minutes).
• Classic monster cookies: To make individual cookies instead of bars, portion and bake as cookies—baking time will vary.
• Gluten-free: Use certified gluten-free oats and ensure your cereal is gluten-free to avoid cross-contamination.

Related Gluten-Free Cookie Ideas

• Vegan Oatmeal Cookies
• Vegan Double Chocolate Chip Cookies
• 5-Minute No-Bake Almond Joy Cookies
• Raspberry Chocolate Chip Oatmeal Cookie Bars