Mordheim: City of the Damned

This should come naturally, just playing the game. The moment you level your warband to 7-10 and can take on missions with higher difficulties more easilly. Look for those that have exceptionel loot. Make a dedicated looter and loot chests. You can get on average 10 recipes each match if you win the mission.

You can also unlock a veteran skill that sometimes sends you a recipe, but it isn't really needed. And useless early game as you lack the gold to use them.

You don't have to collect 100 recipes with one warband (but you'll easilly het there). This counts across warbands, even after you delete a warband and restart.