1-First Step: Preheat your oven to 350°F (175°C). Grease two 9-inch round cake pans with butter or non-stick spray, then line bottoms with parchment paper. This prevents sticking and ensures easy release. Gather all ingredients at room temperature for smooth mixing. Room-temp items blend better, leading to even batter.

2-Second Step: In a large bowl, beat 1/2 cup softened unsalted butter and 1.5 cups sugar with an electric mixer on medium speed until light and fluffy, about 3-4 minutes. Scrape sides often. This incorporates air for a soft vanilla cake. Add 3 eggs one at a time, beating well after each. Follow with 2 tsp vanilla extract. Mixture should look smooth and pale.

3-Third Step: In a separate bowl, whisk 2 cups all-purpose flour, 2.5 tsp baking powder, and 1/4 tsp salt. Sifting removes lumps for better texture. Dry mix ensures even distribution without overmixing later. Set aside while you measure 1 cup milk.

4-Fourth Step: Add dry ingredients to wet mixture in three parts, alternating with milk. Start with half flour, then half milk, repeat, ending with flour. Mix on low speed just until combined, about 30 seconds each time. Overmixing toughens gluten. Batter will be thick and smooth. For extra moisture, stir in 1/4 cup sour cream if desired.

5-Fifth Step: Divide batter evenly between prepared pans, about 1.5 cups each. Smooth tops with a spatula. Tap pans gently on counter to release air bubbles. Bake 25-30 minutes or until toothpick inserted in center comes out clean. Edges pull slightly from pan sides. Rotate pans halfway if your oven heats unevenly.

6-Final Step: Cool cakes in pans 10 minutes, then invert onto wire racks. Peel off parchment and cool completely, about 1 hour. Frost with buttercream: beat 1 cup butter, 4 cups powdered sugar, 2 tsp vanilla, 2-3 tbsp milk until spreadable. Stack layers, crumb coat, chill 15 minutes, then final frost. Slice and serve. Total time: 45 minutes active, plus cooling. Yields 12 servings. Store as below for moist vanilla cake 4 days.