I enjoy baltic porters myself slightly more alcohol and a little darker in color.
Assuming you are doing extract, for 5 gallons I like to steep:
.5 lbs wyerman Carafa Munich 2
1 lbs crystal 60
1 lb chocolate malt
Mix this with 3 pounds of amber extract and 3 pounds of light extract. For additional fermentables it is also possible to as a pound of honey.
The boil I use Nugget Hops about an ounce at 60 minutes and another ounce at 30. I finish it off with an ounce of cascade for the last 5. You can also use Gallena to bitter, but nugget are a bit easier to find these days.
You can use the whitelabs london ale yeast, English ale yeast, Irish Ale Yeast, or in a pinch the california ale yeast. But my preference has been the london ale yeast.
It comes out fairly well, a little hoppier than most porters, but I like that, but to be in style I think I should use less nugget perhaps .75 at 60 and .75 at 30. I hate having 1/4oz and 1/2oz hop packets sitting around so I usually use a full oz whenever I make a recipe. With the honey the OG is usually between 1.65 and 1.7.