I've toasted grains in a frying pan before. Seemed to work just fine, not sure why it's not practiced more frequently.
His recipe is quite different than anything I've seen here:
500g of buckwheat kernels
20g of Pride of Ringwood hop pellets
2kg of maltodextrin (from maize)
850g of Treacle
1 packet of English Ale yeast
Converted to lbs, it would be:
1.1 lbs buckwheat
2 lbs treacle
4.5 lbs maltodextrin (!!!)
0.7 oz Pride of Ringwood hop pellets
Holy carp! 4.5 lbs of maltodextrin?? Does that make sense to anyone? Seems to me like this beer would have a very low ABV, since only the 2 lbs of treacle would be contributing fermentables.