01 - Preheat oven to 350°F. Grease a 9-inch round cake pan with butter and line bottom with parchment paper.
02 - Whisk flour, baking powder, and salt in medium bowl until thoroughly combined. Set aside.
03 - Combine granulated sugar and lemon zest in large mixing bowl. Rub together with fingertips until sugar becomes fragrant and moist.
04 - Add softened butter to lemon sugar. Beat on medium-high speed until pale, light, and fluffy, approximately 3 minutes.
05 - Add eggs one at a time, beating thoroughly after each addition until fully incorporated before adding the next.
06 - Mix in drained ricotta, lemon juice, and vanilla extract on low speed until smooth and uniform.
07 - Gently fold dry ingredients into wet mixture using rubber spatula until just combined. Stop mixing as soon as flour streaks disappear.
08 - Pour batter into prepared cake pan. Spread evenly with offset spatula, smoothing top surface.
09 - Scatter sliced almonds evenly over batter surface. Sprinkle 2 tablespoons granulated sugar across almonds.
10 - Bake for 38 to 42 minutes until golden brown and toothpick inserted in center emerges clean.
11 - Let cake cool in pan 10 minutes. Run knife around edges, invert onto cooling rack, and cool to room temperature.
12 - Dust surface generously with powdered sugar before slicing. Serve at room temperature.