Steeped grains plus malt extract:
Guinness Draught is an iconic stout from Ireland.
Guinness has a slight "tang" that is difficult for homebrewers to replicate. For the adventurous, the recipe suggests fermenting 19 ounces of wort (for 5 gallons) with lactobacillus and brettanomyces. This should be gently heated to 160F (71C) for deactivating these organisms, then add to the main batch before packaging.
Irish ale yeast is recommended. Other English ale yeasts are possible substitutes.
The Brew Your Own Big Book of Clone Recipes, (2018), Guinness Draught, p. 107