1.7kg Coopers Mexican Cerveza extract can (or Muntons Mexican Cerveza etc)

1kg Coopers Brew Enhancer 2 (see here for BE2 ingredients)

100g cracked light Crystal Malt grain

20g Saaz hops** (Cerveza doesn't usually have hops added, but I find it nicer)

Heat in a small saucepan 1.5 litres (1.5 quarts) of water to about 70c/158F.

Stir in the cracked Crystal Malt grain
Place a lid on the saucepan and leave for 20-30mins. (see Steeping here)
Strain the resulting 'tea' into another saucepan.
Rinse the grain with another 1 litre (1 quart) of water at about 70c/158F.
Boil the 2.5 litres (2.5 quarts) of  'tea' for 15mins with the lid off.
Add the Saaz hops and turn off the heat, cover and let sit for 10mins.
Pour the 'tea' and hop mixture into fermenter.
Pour in and dissolve the can of extract and BE2.
Top up the fermenter with cold water to 21 litres (5.5 gallons).
Check temperature of wort and adjust with hot or cold water to get close to 20c/68F at 23 litres (6 gallons).
Mix in yeast when wort is 20c/68F.
Try and let the wort cool down over the next couple of days to as low as 13c/55.5F.
Ferment at 13c-20c (55.5F-68F) for 10 to 14 days.

Bottle or keg as usual.

** The hops are optional.