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Chocolate Oat Flour Mug Cake

Helen T. Patterson
A fudgy and fiber-rich chocolate oat mug cake that’s ready in just minutes!
This single-serve dessert combines oat flour, cocoa powder, and plant-based milk for a wholesome yet indulgent treat.
With peanut butter for protein, coconut oil for good fats, and melty chocolate chips, it’s a quick, gluten-free, and dairy-free cake that feels comforting without the guilt.
Perfect for late-night cravings or an easy anytime sweet fix!
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Prep Time 1 minute
Cook Time 1 minute
Total Time 2 minutes
Course Dessert
Cuisine American
Servings 1

Equipment

  • 1 tall microwave-safe mug (preferably glazed)
  • 1 fork (for mixing)
  • 1 tablespoon (for measuring)
  • 1 teaspoon (for measuring)

Ingredients
  

  • 3 tablespoons oat flour or rolled oats blended into flour
  • 2 tablespoons unsweetened cocoa powder or cacao powder
  • ¼ teaspoon baking powder
  • ⅛ teaspoon fine sea salt
  • 3 tablespoons plant-based milk
  • 1 tablespoon pure maple syrup
  • 1 tablespoon melted coconut oil or avocado/olive oil
  • 1 tablespoon natural peanut butter
  • ¼ teaspoon pure vanilla extract
  • 1 tablespoon dark chocolate chips or chopped chocolate

Instructions
 

  • Prepare Your Mug and Tools: Begin by selecting a tall, microwave-safe mug—preferably one with a smooth glazed surface, as it helps prevent sticking and makes cleaning up a breeze.
    Place the mug on a flat counter so it’s stable while you mix.
    Keep a fork or small whisk nearby for stirring, and measure out all your ingredients before starting.
    Having everything ready ensures the process is smooth and mess-free.
  • Mix the Dry Ingredients: Add 3 tablespoons oat flour, 2 tablespoons cocoa powder, ¼ teaspoon baking powder, and ⅛ teaspoon sea salt directly into the mug.
    Use your fork to stir them together until the mixture looks uniform in color and texture.
    This step is important because evenly mixing the dry ingredients prevents clumps of cocoa or baking powder, which could affect the cake’s rise and overall flavor.
    Think of this as creating a balanced foundation for your mug cake.
  • Blend in the Wet Ingredients: Now, pour in 3 tablespoons of plant-based milk, followed by 1 tablespoon maple syrup, 1 tablespoon melted coconut oil (or your chosen oil), 1 tablespoon natural peanut butter, and ¼ teaspoon vanilla extract.
    Stir slowly at first, then mix more thoroughly, scraping the sides and bottom of the mug to ensure no dry flour is left behind.
    The batter should be smooth, thick, and glossy. Take your time with this step—it’s key to achieving a uniform cake texture without dry pockets.
  • Add the Chocolate for Gooey Goodness: Sprinkle 1 tablespoon of dark chocolate chips (or chopped chocolate) over the top of the batter.
    Gently press them down with your fork so they sink slightly into the mixture but don’t disappear completely.
    This ensures the chocolate melts into the cake as it cooks, creating little gooey pockets of indulgence with every bite.
    If you love chocolate, feel free to add a few extra chips on top as a finishing touch.
  • Microwave and Monitor Carefully: Place the mug in the center of your microwave.
    Start cooking on high power for 50 seconds. Open the microwave and check the cake—the top should look slightly firm but soft in the middle.
    If it’s still wet, continue cooking in 10-second intervals until the cake has risen and the center is just set.
    Avoid overcooking, as this can make the cake dry. Each microwave is different, so treat this step as a “watch closely” moment.
  • Allow the Cake to Rest: Once the mug cake is cooked, carefully remove it from the microwave using oven mitts or a towel—the mug will be very hot.
    Let the cake sit on the counter for at least one minute.
    This short resting time helps the heat distribute evenly, allowing the texture to firm up slightly while remaining fudgy inside.
    Skipping this step may result in a cake that’s too soft to enjoy right away.
  • Garnish and Enjoy Immediately: Your mug cake is now ready to devour! For a simple finish, enjoy it straight from the mug with a spoon.
    To make it extra special, add a drizzle of peanut butter, a few more chocolate chips, or even fresh berries for a refreshing contrast.
    Mug cakes are best eaten warm and fresh, as their soft and gooey texture begins to firm up as they cool. For the ultimate experience, savor it within 5–10 minutes of cooking.

Notes

  • Use the Right Mug: A taller, microwave-safe mug helps prevent overflow and ensures even cooking. Smooth, glazed mugs are best for easy cleanup. Avoid mugs that are too shallow or wide, as the cake may spread too thin and cook unevenly.
  • Measure Ingredients Accurately: Spoon and level your oat flour and cocoa powder for precise measurements. Too much flour or cocoa can make the cake dry or dense.
  • Mix Thoroughly: Ensure all dry ingredients are evenly combined before adding the wet ingredients. Stir gently but completely to form a smooth, lump-free batter.
  • Monitor Microwave Closely: Microwave wattages vary, so check the cake carefully, especially if cooking for the first time. Cooking in short bursts helps prevent overcooking and keeps the texture soft and fudgy.
  • Eat Fresh: Mug cakes are at their best immediately after cooking, while warm and gooey. Waiting too long may result in a firmer, less tender texture.