You can make the crust and filling a day or two ahead, and assemble the tarts when you need them, or make the tarts a day ahead and refrigerate. If you make the crust mixture ahead of time, let it soften for a bit at room temperature to make it easier to handle before forming the tarts For a richer flavor, try toasting the oats, coconut and nuts before using. You can heat them in a fry-pan over medium-low heat until they become fragrant and start to brown slightly. Remove them from the heat immediately and place in the food processor bowl.