Prep the cake pan: Use a 6‑ or 7‑inch round cake pan that fits inside your pressure cooker. Grease it well with oil or butter. Line the bottom with parchment and lightly grease the parchment. If you like a delicate crust, dust the sides with sugar and tap out the excess.

Set up the cooker: Add water to the pressure cooker’s inner pot. Place a trivet or metal rack at the bottom so the cake pan sits above the water. You’re steaming, not boiling.

Cream butter and sugar: In a mixing bowl, beat the softened butter and sugar together until pale and fluffy, about 2–3 minutes. This step builds structure and helps the cake rise.

Add eggs and vanilla: Beat in the eggs one at a time, mixing well after each. Stir in the vanilla. If the mixture looks slightly curdled, don’t panic; it will smooth out with the flour.

Combine dry ingredients: In a separate small bowl, whisk flour, baking powder, and salt. This prevents clumps and ensures even leavening.

Mix the batter gently: Add half the dry mix to the butter mixture and stir just until combined. Add the milk and mix gently. Add the remaining dry mix and stir only until no dry streaks remain. Do not overmix, or the cake can turn dense.

Pan and cover: Transfer the batter to the prepared pan and smooth the top. Cover the pan tightly with foil to prevent condensation from dripping onto the cake surface.

Load the cooker: Place the covered pan on the trivet inside the cooker. Seal the lid. For electric pressure cookers, set to High Pressure for 30–35 minutes. For stovetop models, bring to pressure over medium heat and cook for 25–30 minutes at steady pressure. Times can vary slightly by model and pan size.

Natural release: Let pressure release naturally for 10 minutes, then quick‑release any remaining pressure. Carefully lift out the pan using tongs or a sling.

Check doneness: Remove the foil. A toothpick inserted in the center should come out clean or with a few moist crumbs. If it’s very wet, re‑cover and cook under pressure for another 3–5 minutes.

Cool and unmold: Let the cake rest in the pan for 10 minutes. Run a thin knife around the edge, invert onto a rack, peel off parchment, and flip right‑side up. Cool completely before slicing for the neatest pieces.

Serve simply: Dust with powdered sugar, top with whipped cream, or add fresh berries. The vanilla shines on its own, so keep toppings light.