Line an 8x8-inch square baking pan or a 9x9-inch square baking pan with aluminum foil and spray with non-stick spray.
Crush the vanilla wafers in a food processor. You want them broken up into small pieces but not into a powder. Chop almonds. It really depends on what size you like, but I like to leave them chunky for texture.
In a large bowl, mix all the ingredients except the powdered sugar until they're well combined. The dough will be thick.
Dump the mixture into your prepared pan and smoosh down. Smooth the top flat.
Chill for 30 minutes to 2 hours.
Remove the bars from the refrigerator. With a sharp knife, cut into squares.
Sift the powdered sugar into a bowl. Drop each square into the powdered sugar and cover every side with sugar.
Serve. Store in an airtight container up to 1 week.