Preheat oven to 350°F. Grease a 9-inch round cake pan, and line the bottom with parchment paper; grease parchment. Dust pan with 2 tablespoons of the almond flour. Sprinkle the toasted almonds evenly into bottom of pan.
Place almond paste, sugar, and butter in the bowl of a heavy-duty electric stand mixer fitted with a paddle attachment, and beat on low speed until combined. Increase to medium, and beat until smooth, about 3 minutes.
Add orange zest, 2 tablespoons of the orange juice, liqueur, almond extract, and remaining 1/2 cup of the almond flour; beat on medium speed until smooth, about 1 minute. Lightly whisk eggs; add to almond mixture.
Sift together cake flour, baking powder, and sea salt in a large bowl.
Gently fold almond mixture into flour mixture in 3 parts to combine. The batter will be smooth, but sticky and dense.
Using an offset spatula, spread batter in prepared pan. Tap pan on counter to release any air bubbles. Bake in preheated oven until golden brown and a skewer inserted in center comes out clean, 25 to 30 minutes.
Cool cake in pan on a wire rack 10 minutes. Stir together orange marmalade and remaining 1 tablespoon orange juice in a small microwavable bowl. Microwave on HIGH until warm, about 15 seconds.
While cake is still warm, run a spatula or butter knife along the edge of the cake to loosen it from the pan. Remove cake from the pan by flipping it over onto a cake plate. Discard parchment. Spread the orange marmalade mixture on top of the cake, letting it spill over the sides. Serve with Orange Blossom Mascarpone Cream.
Providence, Los Angeles