One of my favorite beers I've brewed, inspired by a Hoggetowne Ale Works extract recipe that I customized:

Recipe: Smooth Jazz Porter
Style: Brown Porter
TYPE: All Grain (see comments for notes on Partial Mash)

Recipe Specifications
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Batch Size: 5.50 gal
Estimated OG: 1.049 SG
Estimated Color: 35.2 SRM
Estimated IBU: 21.5 IBU
Brewhouse Efficiency: 70.00 %
Boil Time: 60 Minutes

Ingredients:
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Mash

8.00 lb Brewers Malt 2-Row (Briess) (1.8 SRM) 74.42 % - Base Malt
1.00 lb Caramel Malt - 60L (Briess) (60.0 SRM) 9.30 % - Character Malt
1.00 lb Chocolate Malt (350.0 SRM) 9.30 % - Character Malt
0.50 lb Wheat Malt, Pale (Weyermann) 4.65% - Mouthfeel/Body/Head Retention
0.10 lb Black (Patent) Malt (500.0 SRM) 0.93 % - Color Malt
0.10 lb De-Bittered Black Malt (Dingemans) (550.0 SRM) 0.93 % - Color Malt
0.05 lb Carafa Special II (Weyermann) (415.0 SRM) 0.47 % - Color Malt

0.50 tbsp PH 5.2 Stabilizer (Mash 60.0 min)
1.00 gm Gypsum (Calcium Sulfate) (Mash 60.0 min)
2.00 gm Calcium Chloride (Mash 60.0 min)
2.00 gm Chalk (Mash 60.0 min)
2.00 gm Salt (Mash 60.0 min)
3.00 gm Baking Soda (Mash 60.0 min)
3.00 gm Epsom Salt (MgSO4) (Mash 60.0 min)
ca. 8.5 gallons RO water

Mash Schedule: Single Infusion, Light Body, Batch Sparge
Total Grain Weight: 10.75 lb
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Single Infusion, Light Body, Batch Sparge
60 min Mash In 150.0 F


Boil

10.00 gm Magnum [13.00 %] (60 min) 18.1 IBU
12.00 gm Hallertauer Mittelfrueh [3.00 %] (30 min) 2.6 IBU
8.00 gm Goldings, East Kent [4.40 %] (5 min) 0.8 IBU

1.00 items Whirlfloc Tablet (Boil 5.0 min)
6.00 oz Powdered Peanut Butter (Boil 5.0 min)
1/2 tsp Wyeast nutrient

Ferment

1 Pkgs American Ale Yeast (Fermentis #US-05)

Comments

The salt additions are to build RO water up to something resembling English water from the London area.

The color grains (Black Patent, De-Bittered Black Malt, Carafa Special II) in the mash can be simplified to 0.25 lbs of your favorite color malt, preferably de-bittered or de-husked - this beer should not be roasty.

It's good without the powered peanut butter (PB2 brand) as well, but adding it gives it a faint hint of nuttiness that plays very nicely with the chocolate character of the beer. The peanut aroma is fairly strong at first, but fades quickly.

To convert to partial mash, replace part of the 2-row malt with Golden Light (but definitely not Pilsner) malt extract.