📖 Instructions

1. Preheat the Oven: Get started by preheating your oven to 350°F (175°C). Place one of the racks in the center to ensure even baking.
2. Prepare the Pans: Grease two 8-inch round baking pans with butter or cooking spray. Then, line the bottoms with parchment paper rounds. This will help the cakes release easily after baking. No one likes cake stuck to the pan!
3. Cream Butter and Sugar: In a large mixing bowl, cream together 1 cup (2 sticks) of unsalted butter, softened, and 1 3/4 cups of granulated sugar until light and fluffy. This usually takes about 3-5 minutes using an electric mixer. The mixture should be noticeably paler and almost doubled in volume. Don't rush this step; it's crucial for a tender cake.
4. Add Eggs: Beat in 3 large eggs, one at a time, making sure each egg is fully incorporated before adding the next. Then, stir in 2 teaspoons of vanilla extract. I once forgot the vanilla and the cake was just… sad. Don't skip it!
5. Combine Dry Ingredients: In a separate bowl, whisk together 3 cups of all-purpose flour, 2 1/2 teaspoons of baking powder, and 1/2 teaspoon of salt. Make sure there are no lumps in the flour.
6. Alternate Wet and Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, alternating with 1 1/4 cups of milk, beginning and ending with the dry ingredients. Mix until just combined. Be careful not to overmix; overmixing develops the gluten in the flour, resulting in a tough cake. The batter should be smooth but not overworked.
7. Fold in M&Ms: Gently fold in 1 cup of M&Ms. Distribute them evenly throughout the batter. Save a few to sprinkle on top before baking, if you like.
8. Divide Batter: Divide the batter evenly between the prepared baking pans. Smooth the tops with a spatula.
9. Bake: Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean. The cakes should be golden brown on top and spring back lightly when touched.
10. Cool in Pans: Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely. This prevents them from sticking and breaking.
11. Make the Frosting: While the cakes are cooling, make the frosting. In a large mixing bowl, cream together 1 cup (2 sticks) of unsalted butter, softened, and 4 cups of powdered sugar until light and fluffy. Add 1/4 cup of milk and 1 teaspoon of vanilla extract. Beat until smooth and creamy. If the frosting is too thick, add a little more milk, one tablespoon at a time.
12. Frost the Cake: Once the cakes are completely cool, place one cake layer on a serving plate or cake stand. Spread a generous layer of frosting on top. Place the second cake layer on top of the frosting. Frost the top and sides of the cake with the remaining frosting. Decorate with additional M&Ms, if desired.
13. Chill (Optional): For easier slicing, chill the cake in the refrigerator for at least 30 minutes before serving. This allows the frosting to set and the cake to firm up.
14. Serve: Slice, serve, and enjoy your delightful Vanilla Birthday Cake with M&M Surprise! Watch the smiles as everyone discovers the hidden M&Ms.