Preheat the oven to 350 degrees Fahrenheit.
Prepare the cake pan. Spray the pan lightly with oil and cover the bottom with parchment paper, making sure it covers all the way up to the edges as the sugars in the cake tend to stick. Dust the cake pan with a tablespoon of flour.
In a large bowl or the bowl of a stand mixer, beat together the butter and sugar until fluffy, about a minute.
Add the lemon juice and zest, nondairy milk, all purpose flour, almond flour, tapioca stach, baking powder and baking soda to the bowl and whisk 15 seconds until just incorporated. You can use the whisk attachment if using a stand mixer. Scrape down the sides and the bottom of the bowl to ensure everything is mixed and beat 10 seconds more.
Pour the batter into the prepared pan and smooth the top lightly with a spatula.
Bake the cake for 25 minutes, then pull it out of the oven and pour the lemon curd into the center. Spread it slightly leaving a one-inch border all around the edges.
Sprinkle with the sliced almonds, if using, then return the cake to the pan and bake 10 more minutes until it looks golden -brown. A toothpick inserted in the cake should come out clean (although some lemon curd might stick, which is okay).
Let the cake cool for 20 minutes on a rack, then gently remove the sides of the springform pan and continue cooling on the rack.
Slice and serve when cooled thoroughly.