Beat egg yolks, oil and vanilla with electric mixer fitted with whisk attachment on medium speed until well blended. Gradually drizzle water into mixture while mixing on medium speed. Add 8 oz. sugar, flour, baking powder and salt. Beat on high speed 2 min.

Combine egg whites and remaining 8 oz. sugar in second mixer bowl. Beat on high speed with whisk attachment until a soft-peak meringue forms. Fold meringue into egg yolk mixture. Divide batter evenly between 2 parchment paper-lined half-sheet pans.

Bake in 375°F standard oven 15 to 20 min. or until wooden pick inserted in center comes out clean. Remove from oven; cool completely in pans on wire rack. Freeze cakes in pans 1 hour for ease in removing parchment paper.

Remove cakes from freezer. Invert pans and carefully remove parchment paper. Use 4-1/2-inch round cutter to cut 7 circles from each cake. Cover with plastic wrap and store at room temperature until ready to make into "tacos."

Meanwhile, spread ice cream onto parchment paper-lined full sheet pan to about 1/2-inch thickness. Freeze several hours or until firm. Use 4-1/2-inch round cutter to cut out 14 ice cream circles. Remove 1/2-inch circle from center of each ice cream circle using small round cutter. (Discard small ice cream pieces or save for another use.)

Place 1 ice cream circle on top of each cake round. Fold in half to form a "taco."

Dip open edge of each taco into melted semi-sweet chocolate. Sprinkle with some of the OREO Small Pieces. Drizzle with some of the melted milk chocolate. Freeze on parchment paper-lined sheet pan until ready to serve, using crumpled waxed paper between each taco to hold it in an upright position.