Place the pecans in a blender; cover and process until ground. Set aside 1 cup for cake (save any remaining ground nuts for another use). In a microwave, melt chocolate chips and butter; stir until smooth. Cool to room temperature.
In a large bowl, beat egg yolks and 1/2 cup sugar until slightly thickened; stir in cooled chocolate mixture. Combine flour and reserved ground nuts; stir into egg yolk mixture. Set aside.
In another large bowl, beat egg whites and cream of tartar on medium speed until soft peaks form. Gradually beat in remaining sugar, 1 tablespoon at a time, on high until stiff glossy peaks form and sugar is dissolved. Fold a third of the egg whites into batter, then fold in remaining whites.
Spoon into a greased and waxed paper-lined 9-in. springform pan. Bake at 350° for 35-40 minutes or until a toothpick inserted in the center comes out with moist crumbs. Cool on a wire rack. (Cake top will puff, then fall during cooling.) Gently push down top and sides of cake to even surface. Run a knife around edge of cake to loosen. Remove sides of pan; invert cake onto a plate and gently peel off waxed paper.
For glaze, heat chocolate chips and cream in a microwave until melted; stir until smooth. Cool until slightly thickened. Spread a thin layer of glaze over top and sides of cake. Pour remaining glaze over cake; spread over top and sides, allowing glaze to drip down sides. Chill until glaze is set, about 30 minutes. Cut into wedges.
Editor’s Note: This cake uses only 2 tablespoons of flour, so the texture is very dense.