Preheat oven to 375°F. Grease a 15-by-10-inch jelly-roll pan; line with parchment paper.
Make chocolate roll: Using an electric mixer, beat egg yolks and 1/2 cup granulated sugar for 4 minutes. Add cocoa and vanilla; mix at low speed.
Beat egg whites and salt in a bowl at medium speed for 2 minutes. Add 1/4 cup granulated sugar; beat at high speed until stiff. Fold one-third of egg whites into cocoa mixture; fold in remaining whites; blend. Scrape batter evenly into pan. Bake until springy, about 15 minutes.
Sprinkle confectioners' sugar on cake, run a knife around edges, cover with a towel and invert. Remove parchment. Roll up from a long side in towel.
Make filling: Using a mixer, beat cream, sugar and vanilla until stiff. Fold in ricotta.
Make glaze: Melt chocolate in cream. Beat in corn syrup.
Gently unroll cooled cake. Evenly spread ricotta filling; roll from a long side. Spread on chocolate glaze. Sprinkle pistachios on roll, if desired.