How to Make It
To prepare cake, coat a 15 x 10-inch jelly-roll pan with cooking spray; line bottom with wax paper. Coat wax paper with cooking spray; dust with 2 tablespoons matzo meal.
Preheat oven to 350°.
Combine pecans, 1/4 cup matzo meal, 2 tablespoons Praline Powder, and baking soda in a food processor. Pulse 6 times or until coarsely ground.
Combine 1 teaspoon vinegar, 1 teaspoon vanilla, 1/4 teaspoon salt, and 8 egg whites in a large bowl. Beat with an electric mixer at high speed until foamy. Gradually add 1/3 cup sugar, 1 tablespoon at a time, beating until stiff peaks form. Combine 4 egg yolks and remaining 1/3 cup sugar in a medium bowl; beat until thick and pale, about 2 minutes. Stir in matzo mixture. Gently stir one-fourth of egg white mixture into egg yolk mixture; gently fold in remaining egg white mixture.
Gently spread batter into prepared pan. Bake at 350° for 12 minutes or until cake springs back when touched lightly in center. Loosen cake from sides of pan, and turn out onto a dishtowel dusted with remaining 2 tablespoons matzo meal; carefully peel off wax paper. Cool 1 minute. Starting at end, roll up cake and towel together. Place, seam side down, on a wire rack; cool.
To prepare filling, beat 1 teaspoon vinegar, 1/4 teaspoon vanilla, 1/8 teaspoon salt, and 3 egg whites with a mixer at high speed until foamy using clean, dry beaters. Combine 1/2 cup sugar and 1/2 cup water in a saucepan; bring to a boil. Cook, without stirring, until a candy thermometer registers 250°. Pour hot sugar syrup in a thin stream over egg whites, beating at high speed until stiff peaks form, about 3 minutes.
Unroll cake carefully; remove towel. Place about 1 cup of filling in a small zip-top plastic bag. Spread remaining filling over cake, leaving a 1/2-inch margin around outside edges. Sprinkle 3 tablespoons Praline Powder over filling. Reroll cake; place, seam side down, on a platter. Snip off an 1/8-inch opening in 1 bottom corner of bag; pipe filling over the top of roulade. Sprinkle with remaining 1 tablespoon Praline Powder.