If you want authentic, your base malts should be mostly Munich/Vienna, with some Pilsner. Then add some darker crystal to give a bit of dark fruit character. Like Thirsty_Monk said, keep the roast down. Use lager yeast. My recipe is:
61% Munich
31% Pilsner
5% Special B
2% Chocolate
1% Carafa III
OG 1.088
40 IBUs of noble hops
California Steam yeast at 60°F