I have mentioned this before but I am not a fan of modifying desserts to make them flour/gluten free. If you need to steer clear of flour or gluten, I suggest simply baking items that do not call for those elements in the first place. And I promise, there are tons of wonderful recipes out there (like these almond cookies or lemon almond meringues or this clementine cake).
Another amazing option is this chocolate hazelnut macaroon cake from Smitten Kitchen: 100% flour/gluten free, 100% delicious, and 100% perfect for a summer barbecue.
Chocolate Hazelnut Macaroon Torte
from Smitten Kitchen (link has a wonderful tutorial!)
Make macaroons: Preheat oven to 325°F. Outline four 8-inch circles on individual pieces of parchment paper. Turn each sheet of parchment over so your ink lines don’t transfer onto the macaroon, place each piece of parchment paper on large baking sheets, and lightly coat each piece of parchment with oil or butter (or spray oil).
Mix hazelnut flour, 1 cup sugar, and salt until fully combined. Beat egg whites in the bowl of a stand mixer with whisk attachment until soft peaks form. Slowly add vanilla extract, then slowly add remaining 2 tablespoons sugar. Beat until stiff but not dry. Gently fold nut mixture into egg whites in 1/3 increments.
Using a spatula (offset, if you have it), spread 1/4 of macaroon batter evenly within each circle. Bake layers until golden and dry to the touch: 20-23 minutes but check on the earlier side as every oven is different. Cool macaroons on their sheets on a cooling rack.
Make chocolate filling: Heat half of the chocolate, water, and coffee in a small saucepan over low heat, stirring until smooth. Remove from the heat and stir in second half of chocolate chunks until melted. Let the mixture cool a bit to lukewarm and then spread chocolate evenly over tops of meringue rounds. Cool each disc until chocolate is set: speed up the process by placing each meringue in the freezer for a few minutes until firm.
Make whipped cream: Beat cream with sugar and vanilla in a bowl with whisk attachment until stiff peaks form.
Assemble torte: Peel the parchment off the back of each macaroon round. Arrange your first macaroon on your serving plate. Spread 1/3 cup whipped cream over the first disc. Repeat with second and third macaroon rounds, then top with final round. Frost top and side of torte with whipped cream.
Oil or butter for greasing parchment rounds
1 cup plus 2 tbsp granulated sugar
6 large egg whites
2 1/2 cups hazelnut flour/meal
1/4 tsp table salt
1 tsp vanilla
1 cup bittersweet chocolate, coarsely chopped
1/4 cup water
1 tsp instant coffee
Whipped Cream for Frosting
1 1/2 cups chilled heavy cream
3 tbsp granulated sugar
1 tsp vanilla