Preheat your oven to 325°F. Butter a 7-inch springform pan generously and dust with flour, tapping out the excess. If using a fixed pan, line the bottom with a circle of parchment and butter the sides very generously. A springform is strongly preferred here as getting a ricotta torte out of a fixed pan cleanly is difficult.

Beat the softened butter and sugar together in a large bowl until combined and slightly lightened. Add the eggs one at a time, beating well after each. Add the ricotta and beat until completely smooth with no lumps remaining. If your ricotta is grainy pass it through a fine mesh strainer before adding. The texture of the finished torte depends entirely on the smoothness of the ricotta at this stage.

Add the flour, lemon juice, lemon zest, vanilla and salt. Mix until everything is fully incorporated and the batter is smooth and pourable.

Pour the batter into the prepared pan. Fill no more than ¾ full. Place the pan on the bottom rack of the oven. This is the documented Patsy's instruction and produces a gently, evenly set torte without aggressively browning the top. Place a small baking sheet on the rack below to catch any overflow.

Remove from the oven and allow to cool completely at room temperature before touching the springform latch. Once fully cooled, refrigerate for a minimum of 3 hours. Overnight is better. The torte must be served cold. The texture when cold is completely different from when warm, firmer, creamier and more sliceable.

Run a thin knife carefully around the edge of the pan before releasing the springform. Serve in slices. Dust with a little powdered sugar before serving if you want a cleaner presentation.