Combine the lentils and the water in a 2-quart saucepan over medium-high heat and bring to a boil. Reduce heat to medium-low, cover with a lid, and simmer for 30 minutes, until most of the liquid has evaporated and lentils are very tender. Remove from heat and puree in a food processor until smooth, about 15-20 seconds. Set aside to cool to room temperature.
Place one oven rack in the top third of the oven and another in the bottom third and boost the heat to 350ºF.
Combine the flour, baking powder, salt, cinnamon, and allspice in a medium mixing bowl.
Combine the sugar and butter in the bowl of a standing mixer fitted with the paddle attachment. Mix for 3 minutes on medium speed until light and fluffy. Add the egg and vanilla, followed by the lentil puree and mix until thoroughly combined. Turn the speed to low and add the flour mixture a little a time until just combined. Remove the bowl from the mixer and fold in the oats, dried fruit, and coconut.
Form the dough into balls about 2 teaspoons in size using #100 disher or spoon and place on a parchment paper-lined half-sheet pan, leaving about 1 inch between each ball. You should be able to fit 24 balls per sheet pan. Bake, 2 sheets at a time for 8 minutes, then swap the top pan and the bottom and rotate them 180 degrees. Continue baking for another 7 minutes until the internal temperature reads around 200ºF on an instant-read thermometer. Repeat this process until all cookies are baked.
Cool on a cooling rack for 10 minutes before devouring.