Prep the pans: Preheat oven to 350°F (175°C). Grease three 8-inch round pans, line with parchment, and lightly flour. Set aside.

Mix the dry ingredients: In a large bowl, whisk flour, baking powder, baking soda, and salt. Set aside.

Cream butter and sugar: In a stand mixer, beat butter and granulated sugar on medium-high until light and fluffy, about 3 minutes.

Add eggs and vanilla: Mix in eggs one at a time, scraping the bowl as needed. Add vanilla and mix until smooth.

Combine with buttermilk: On low speed, add dry ingredients in three parts, alternating with buttermilk. Start and end with the dry. Mix just until combined.

Bake: Divide batter evenly among pans. Bake 22–26 minutes, or until a toothpick comes out clean and the tops spring back.

Cool completely: Let layers cool in pans for 10 minutes, then transfer to a rack. Cool fully before frosting. For neat layers, wrap and chill 30–60 minutes.

Make the buttercream: Beat butter on medium-high until creamy, 2 minutes. Add half the powdered sugar, mix on low, then add remaining sugar, cream, vanilla, and salt. Beat 3–4 minutes until fluffy. Adjust with a splash more cream for spreadability.

Level the cakes: If needed, trim domed tops with a serrated knife for flat, even layers.

Assemble: Place one layer on a turntable or stand. Spread a thin layer of buttercream, pipe a border, and add a thin layer of jam (optional). Top with the second layer and repeat. Place the final layer upside down for a flat top.

Crumb coat: Spread a thin layer of buttercream over the entire cake to lock in crumbs. Chill 20 minutes.

Final coat: Apply a thicker, smooth layer of buttercream. Use a bench scraper to smooth sides and an offset spatula to clean the top edge.

Decorate elegantly: Add a subtle chocolate drip, arrange berries, dust edges with luster dust, or add pearls and a topper. Keep the design clean and chic.

Chill and serve: Chill 30–60 minutes to set. Bring to room temperature for 20–30 minutes before slicing for the best texture.