Bake sponge. Pre-heat oven to 350 °F (175 °C). Line an 8-inch pan. Whip eggs and sugar until pale and tripled. Fold in sifted flour, cocoa and baking powder, followed by vanilla, milk and oil. Bake 15-18 min; cool completely.
Cook raspberry base. Simmer raspberries, sugar and lemon 8 min. Sieve; you need ~¾ cup puree. Bloom gelatin in cold water; melt into warm puree. Cool to room temperature.
Whip mousse. Beat chilled cream to soft peaks; fold through raspberry mixture.
Assemble core. Line an 8-in (20 cm) ring with acetate. Place sponge in base, add mousse, level and chill ≥2 h.
Finish with ganache. Heat cream to a simmer; pour over dark chocolate, stand 2 min, then stir glossy. Add vanilla. Spread over set mousse; chill 1 h.
Prepare mirror glaze. Bloom gelatin in water. Heat sugar, water, glucose and condensed milk to 185 °F (85 °C). Remove, stir in white chocolate and gelatin until smooth. Tint if desired; cool to 95 °F (35 °C).
Glaze. Unmold entremet onto a rack. Pour glaze from centre, letting it cascade evenly. Trim drips once set (≈10 min).
Serve. Transfer to platter. Cut with a hot, dry knife for pristine slices.