How about cream puffs filled with lightened lemon curd? Make a pate a choux using cake meal in place of flour and lighten your curd with either whipped real cream or whipped non-dairy cream. Either pipe in the filling or split the puff and spoon in the filling. You can even sift over confectioners' sugar (grind regular sugar with potato starch) and scatter blueberries or sliced strawberries around the plate, if you'd like.
Great-Aunt Irene's Sponge Cake
A classic example of the form, in my opinion.
10 eggs, separated
1 3/4 cups sugar
1/3 cup orange juice, or juice of one large orange
Juice of 1 lemon, about 3 tablespoons
3/4 cup matzah cake meal
1/2 cup potato starch
Preheat oven to 350 F.
Whip egg whites with 1/4 cup sugar until stiff peaks form; refrigerate. Separately, beat yolks with remaining 1 1/2 cups sugar until thick. Add orange and lemon juices to yolks, beating until thick. Stir in dry ingredients, then fold in whites. Bake in ungreased tube pan for 55-65 minutes, or until an inserted tester comes out clean. Remove from oven and immediately invert pan to cool; generally, it's easiest to do this by inserting a narrow-necked wine bottle into the hole in the center of the tube pan, then flipping the whole thing over. (Before pouring batter into pan, test wine bottles to see which of yours fits your pan.) Cool completely before turning right side up.
It's not lemon, but chocolate mousse is really easy to make if you have an electric mixer. Serve with strawberries. You could probably make a lemon mousse too, and serve with meringue cookies.
I've made this one before, and it is really nice. Substitute whipping cream with KFP non-dairy whip.
Fill a pie plate with a simple meringue, spreading the center more thin and building up the sides. Bake. Fill with lemon curd.
Chocolate Dipped Strawberries:
Melt bittersweet chocolate with some parve margarine or butter over low heat. Stir until smooth. Remove white yomtov shirts from small boys and fancy dresses from small girls. Put chocolate on the table with strawberries or other fresh fruit , and let our people dip.
Flourless chocolate torte (can be done without the ringform pan, although it is lovely to use one and garnish with fresh raspberries and, perhaps, a simple raspberry sauce or coulis
Baked Apples - is there anything better than a warm baked apple?
Fruit poached in spiced wine
Cheescake for a milchig meal (yes, virginia there are Jews who eat a milchig lunch on yomtov) Make a crust of ground nuts with a pat of melted butter, a little sugar, and a dash of cinnamon.
Notice that none of these uses matzo or cake meal, so none has that Pesachdik tam.