Chunky Monster Cookie Bars

Name: Chunky Monster Cookie Bars
Prep time: 12 min
Cook time: 27 min
Total time: 39 min
Yield: 9 servings
Ingredients: 1 1/2 cups all-purpose flour; 1 teaspoon cinnamon; 1 teaspoon baking soda; 1/2 teaspoon salt; 3/4 cup melted unsalted butter; 1 cup packed light brown sugar; 1 tablespoon vanilla extract; 1 tablespoon maple syrup; 1 large egg; 1 1/2 cups old-fashioned rolled oats; 1 cup M&Ms; 1 cup semi-sweet chocolate chips

By Emma

Certified Culinary Professional

Published on 15 February 2026 • Recipe tested & approved

Oats, cinnamon, M&Ms, and chocolate chips meld in chewy bars. Brown sugar and melted butter give caramel notes. Maple syrup swap adds earthiness. Baked golden, soft but set. A candy-studded feast for any sweet tooth craving.

Prep: 12 min

Cook: 27 min

Total: 39 min

Servings: 9 servings

#American #dessert bars #candy cookies #baking tips #chewy cookies

Before You Start

The messy, colorful chaos of M&Ms and chocolate chips stuffed into a thick oat dough. Each bite bursts chewy oats, cinnamon warmth, and buttery brown sugar caramel notes. Maple syrup sneaks in a forest-floor earthiness that smooths the sweetness. I swapped baking powder for baking soda after too many bars feeling cakey, aiming for the right density. I’ve found melting butter crucial — chunks wreck texture, causes uneven cooking. Temperature nuances matter too — the edges crisp and golden, center springy, signals readiness better than rigid timers. Cooling? Don’t rush. Slicing warm bars is gummy chaos, patience pays off. A candy-studded, soft bar someplace between cookie and granola. Something I always reach for after baking experiments left me wanting wholesome but none-too-sweet treats. Try swapping chips for nuts or dried fruit if M&Ms are scarce — go easy on mix-ins or dough turns dense, you’ll smell caramel and cinnamon before even touching the oven. Good luck chasing perfect chewy.

Ingredients

1 1/2 cups all-purpose flour
1 teaspoon cinnamon
1 teaspoon baking soda
1/2 teaspoon salt
3/4 cup melted unsalted butter
1 cup packed light brown sugar
1 tablespoon vanilla extract
1 tablespoon maple syrup
1 large egg
1 1/2 cups old-fashioned rolled oats
1 cup M&Ms
1 cup semi-sweet chocolate chips

About the ingredients

Flour variations will change uptake — use all-purpose for balance. Tried whole wheat once; taste got grassy, texture denser, acceptable but not charming. Cinnamon isn’t just spice; it sneaks flavor depth and warmth, don’t skip or cut in half. Baking soda instead of powder lights a bit more lift, but measure precisely — too much makes metallic taste. Melted butter is non-negotiable — room temp chunks cause pitting and uneven caramelization. Brown sugar provides moisture and rich molasses flavor versus granulated sugar’s dryness. Maple syrup swap keeps bars moist with earthiness often missed in standard recipes. Egg helps bind, no substitute with applesauce or flax without adjusting dryness elsewhere. Oats absorb moisture and bring chew; rolled oats preferred, instant oats too soft, steel-cut too tough. M&Ms add crunch and bursts of candy-coated sweetness; chocolate chips melt, swirl. Could swap nuts or dried cranberry for different textures. Salt balances sweetness, never omit. Vanilla deepens flavors but can be halved or replaced with almond extract for loggerhead experiments.

Method

Heat oven to 350 F and lightly grease a 8x8 inch pan or line with parchment, leaving overhang on sides — this sling makes lifting bars easy.
In a medium bowl, whisk together flour, cinnamon, baking soda, and salt. Baking soda swaps for baking powder here for a punchier rise and better chew after trial runs.
In a bigger bowl, stir melted butter into brown sugar. Don’t skip melted butter — patches happen with cold chunks, uneven sweetness.
Add vanilla, maple syrup, and egg into butter-sugar mixture. Beat till no streaks. Maple syrup is a twist from original; deeper flavor, subtler sweetness versus just vanilla.
Dump dry ingredients and oats into wet. Use a spatula — nothing electric or you overmix gluten. Shaggy dough is the aim.
Fold in M&Ms and chocolate chips evenly. Bike between stirring and folding to not crush candies too early or clump chocolate all bottom.
Transfer dough to pan. Press gently with offset spatula until flat but don’t compact overly — bars lose chewy air pockets otherwise.
Slide pan onto center rack. Bake ~27 minutes or until edges brown and center looks set but springy when poked. Watch after 20 min, oven heat varies. Toothpick with moist crumbs ok — too dry means overbaked.
Cool bars completely in pan. Warm bars get gummy and cut messy. Use parchment sling to lift out, cut into 9 even squares with a sharp knife cleaned between slices.
Leave comments or stars if you played with ingredients but don’t skip that cooling step — huge difference in texture.

Cooking tips

Prep matters. Sift or whisk dry ingredients—clumps kill even rise and lead to weird dry pockets. Mixing order? Melted butter beating well with sugar ensures caramelized chewy bites. Add egg and liquids after sugar blends for emulsification. Fold dry and oats slowly but thoroughly; overmix and bars toughen. Candy should be last and handled gently — mash M&Ms too much, colors bleed and dough darkens. Using an offset spatula for flattening helps spread dough evenly without compressing, preserving texture. Oven preheat must be full 350 F; too low means underdone doughy center, too high edges burn first. Watch colors — golden edges with a springy center mean done. Toothpick checks should catch moist crumbs not gooey batter. Cooling in pan avoids breaking but bars remain fragile warm — sharp knife cooled cleans slices. Slice into nine — uniform squares bake more evenly than random chunks. Leftover dough freezes well; thaw overnight in fridge, bake same way. Expect small changes in timing depending on ovens, use sensory cues over clock.

Chef's notes

💡 Butter must be fully melted not warm chunks or texture wrecks. Cold bits cause uneven caramelization spots, makes bites weird. Brown sugar needs soft and packed tight for moisture but not sticky mush. Maple syrup adds moisture and rich flavor but swap carefully, too much flips texture. Use old-fashioned oats, not instant or steel cut. They keep chew, structural balance. Dry ingredients sifted or whisked avoids dry pockets—it’s key for even rise without weird lumps.
💡 Don’t rush folding candies. M&Ms color bleeds fast if mashed. Fold softly, gently, half stir half fold work well so chocolate doesn’t clump bottom. Use offset spatula for flattening dough in pan—press just enough to spread without compacting. Too much pressure kills air pockets, bars turn dense. Oven at full 350 F, preheat completely. Underheat makes gooey middle, overheat burns edges before center cooks through.
💡 Watch for visual cues not just timer. Edges golden brown, centers look set but wobble slightly when poked. Toothpick moist crumbs okay—don’t want bone dry, means overbaked. Bars springy, not stiff when pressed. Cool fully in pan on rack—warm bars slice gummy, fall apart. Parchment sling helps remove bars cleanly without breakage, cuts neat squares. Slicing knife cooled and wiped between cuts prevents dragging and uneven slices.
💡 Swapping nuts or dried fruit changes chew and density. Go easy on add-ins or dough thickens too much, bars lose airy texture. Cinnamon adds warmth, don’t skip or reduce too much, it sneaks in depth you won't notice till it's gone. Baking soda swap for powder adds punchy rise, but measure exact or bars metallic and off. Vanilla can be halved or swapped almond extract—changes flavor base subtly. Egg crucial for bind, no simple swap without adjusting liquids elsewhere.
💡 Leftover dough freezes well. Thaw overnight in fridge, bake same temp/time. Mix order matters—dry ingredients combined first then folded in avoids overmix. Melted butter beaten in brown sugar gives caramelization. Add liquids after sugar blends fully for good emulsification. Cooling step often skipped; hugely changes texture. Too quick slicing equals gummy mess; patience pays in cutting cleaner bars with clear chew and defined crumb.

Common questions

What if butter isn’t fully melted?

Chunks stay cold, cause uneven spots. Texture patchy. Bars get pitted, caramelization breaks down. Melt fully, stir smooth before mixing. Avoid temperature shifts so sugar blends evenly.

Can I replace maple syrup?

You can swap with honey or molasses but moisture and flavor shift. Maple adds earthiness not sweetness punch. Honey might sweeten too much, molasses makes darker dough. Adjust brown sugar slightly if experimenting.

Why are bars gummy after baking?

Usually sliced too warm or underbaked. Edges brown, center set but bars hot inside. Cool completely in pan, sits firm. If baked less, centers stay moist, gummy texture. Timing and cooling crucial here.

How to store leftovers?

Wrap tightly, fridge or room temp in airtight container. Freeze for longer. If refrigerated, bring to room temperature before eating for chew. Avoid moisture exposure or bars get hard outside, chewy inside uneven.