Need some help with a partial mash Stout

Quick synopsis of my experience since I'm new to the forum (been lurking however). I have made two batches of beer in about 1 month time. The first was a Orange Honey Blossom Wheat recipe at my local homebrew store. This used extract, honey, and wheat grain for fermentables. Second (which is ready to be bottled) is a recipe called Hop Lava IPA that was also from the homebrew store. The fermentables used in this were partial mash as well (more extract AND grain than the first recipe).

I'm wanting to try my own concoction for once, in the form of a winter stout. I found a recipe cloning a microbrew I like, and I am basing my beer off of that (and adding some non fermentable flavoring). The problem is, the recipe is all grain. I simply don't have the equipment/space to do this efficiently.

So my question is, how can I get something comparably "stouty" with a partial mash (using a good amount of extract for sugars). The grains used in the recipe are as follows:

14.75 lbs Pale Ale malt
3.25lb Crystal/Caramel Malt
1.0 lb Lactose.

I'm assuming my best bet would be using a Pale Ale malt extract, and adding the Crystal/Caramel Malt as mash.

Problem 1 is: What extract do I use?
Problem 2 is: What amount of extract do I need?

Or is this a bad idea??? Help please! Time is running out to have this ready in a timely manner for the holiday season!

I believe the conversion of all grain to DME is .6 so if you used 8.85 lbs of DME that should give you the equivalent of using the 14.75Lbs of pale malt. I'd go with any if the light DME choices available.

Thank you.

If you use DME to replace all the pale ale malt, you won't really be "mashing" the crystal, you'll be "steeping" it. That's fine, of course, but good to know the terminology.

If you want to do a partial mash, keep some of the pale ale malt in your recipe. Figure out how much grain you can mash, subtract that from the bill and make up the difference with DME. The 0.6 conversion factor is a good route, but if you want to be in more control of your OG, you can measure the gravity post-mash and adjust the amount of DME up or down to hit your target. Not essential, though, and the more DME you plan to use to begin with, the less important this is.

Regarding your recipe, without some roasted barley or roasted malt in there, you're not going to get the typical roastiness that stouts require. This isn't necessary for making good beer, but if you're interested in brewing something that meets the traditional definition of the stout, you may want to look into that.