Microwave Peanut Butter Bar

Prep: 10 min Cook: 7 min Serves: 12 Cuisine: American

A quick and delicious microwave peanut butter bar with crunchy peanuts and a sweet, chewy base, perfect for satisfying a sweet tooth in minutes.

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Ingredients

  • 1/2 cup margarine
  • 1 cup brown sugar
  • 1/2 cup peanut butter
  • 1 egg
  • 1 1/2 cups all-purpose flour
  • 1 teaspoon baking powder
  • 1/4 teaspoon salt
  • 1 cup roasted peanuts

Instructions

  1. Microwave margarine in a 2-quart casserole dish on High for 30 seconds.
  2. Add brown sugar, peanut butter, and beaten egg to the melted margarine.
  3. Mix well to combine.
  4. In a separate bowl, combine all-purpose flour, baking powder, and salt.
  5. Add the dry ingredients to the sugar mixture and mix well.
  6. Stir in chopped roasted peanuts.
  7. Pour the mixture into a greased 8-inch square dish.
  8. Microwave on Medium for 5 to 7 minutes.
  9. Rotate the dish 1/2 turn after 3 minutes of cooking.
  10. Let the bars stand on the counter to cool before cutting into pieces.

Tips & Substitutions

For a creamier texture, consider using smooth peanut butter instead of crunchy. If you don't have margarine, unsalted butter can be a suitable substitute. To enhance the flavor, try adding a teaspoon of vanilla extract. Make sure to check the bars in the microwave a minute early to avoid overcooking, as microwave power can vary significantly.

Serving Suggestions

These peanut butter bars are delightful on their own, but you might also enjoy them with a scoop of vanilla ice cream for a decadent dessert. They pair beautifully with a glass of cold milk or a hot cup of coffee. For a fun twist, try drizzling melted chocolate over the top or serving alongside Rice Krispy Dessert for a variety of textures.

Storage & Reheating

Store any leftover bars in an airtight container at room temperature for up to a week. For longer storage, you can refrigerate them for up to two weeks. If you want to enjoy them warm, briefly microwave individual pieces for about 10-15 seconds before serving to regain their softness.

Nutrition & Diet Analysis (per serving)

Each serving of Microwave Peanut Butter Bar contains roughly 217 calories, with 5g protein, 42g carbohydrates, and 3g fat. It is a good source of iron (11% of the Daily Value), protein (10% of the Daily Value), and calcium (10% of the Daily Value). Note that it is relatively high in sodium, at 796mg per serving (35% of the Daily Value).

217 kcal 11% DV
Protein Fat Carbs

Macronutrients

Protein 4.8g 10% DV
Total Fat 3.4g 4% DV
Carbs 42.3g 15% DV
Fiber 1.2g 4% DV
Sugar 10.1g 20% DV

Electrolytes

Sodium 795.6mg 35% DV
Potassium 131.1mg 3% DV
Cholesterol 25.8mg 9% DV

Vitamins & Minerals

Vitamin A 6.3mcg 1% DV
Vitamin C 0mg
Calcium 126mg 10% DV
Iron 1.9mg 11% DV
Diet fit Under 400 cal Low-fat
Contains Milk Egg Wheat/Gluten Peanut

Estimated from ingredients & per-serving nutrition — verify against package labels for allergies or strict diets.

* % Daily Values based on a 2,000 calorie diet (FDA 2020).

Frequently Asked Questions

Can I use crunchy peanut butter instead of smooth?

Yes, crunchy peanut butter can be used for added texture and flavor. It will give your bars a delightful crunch, making them even more enjoyable. Just ensure to mix it well with the melted margarine and sugar to maintain the consistency.

How do I know when the bars are done cooking?

The bars are done when the edges start to pull away from the sides of the dish and the center is set but still slightly soft. A toothpick inserted in the center should come out mostly clean. Remember, they will continue to firm up as they cool.

Can I add other mix-ins to this recipe?

Absolutely! Feel free to incorporate chocolate chips, dried fruits, or even shredded coconut to customize your bars. Just keep in mind that adding extra ingredients may affect the cooking time slightly, so monitor them closely in the microwave.

Nutrition is estimated from USDA FoodData Central ingredient data and may vary with brand, portion and preparation — see our methodology. This information is for general educational purposes only and is not medical or dietary advice (disclaimer).

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