CURD: combine zest, juice, sugar, salt and eggs in a saucier and beat well. Add butter, and place over medium heat. Cook, whisking constantly, then with a rubber spatula, until mixture thickens into curd, about 5 min. Strain into a bowl, and press plastic wrap onto surface. Refrigerate until cool, at least 1-1/2 hours.

CAKE: Heat oven to 350 degrees. Grease 9-inch spring-form pan with 1 tablespoon butter, and cover bottom with parchment round

With an electric mixer, cream butter and 1 cup sugar together until light and fluffy. Sift together the remaining flour, baking powder and salt, and stir in.

In a separate bowl, whisk eggs until they start to foam. Do not overbeat or the cake will be tough. Add eggs and ground almonds to batter, and mix well. Scrape batter into the prepared pan.

Drop 8 individual tablespoons curd evenly around perimeter of batter, leaving a 1 border. Drop 3 to 4 tablespoons curd into center of batter.

Sprinkle cake with toasted almonds and 1 to 2 tablespoons sugar, depending on taste.

Bake until brown on top and toothpick inserted into cake (not curd) comes out clean, about 40 min.

Let cool on rack 10 minutes, then remove sides of pan, and cool completely.

Whip cream with almond liqueur. Present cake at table, and offer whipped cream on the side.