In a small saucepan, add lentils and water. Bring to a boil over high heat, reduce to medium and simmer for 10 minutes. Remove from heat, drain and cool.

Transfer cooked lentils to a food processor and puree until smooth.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter until light and fluffy. Add pureed lentils, and egg and beat until combined.

Beat in icing sugar, vanilla and salt.

Add in flour and mix until just combined.

Turn the dough out onto a lightly floured surface. With floured hands, divide the dough in half and roll each half into a log about 8 inches long and 2 inch in diameter. Wrap in plastic and refrigerate for at least 1 hour, or overnight.

Preheat oven to 350 degrees F. Line baking sheet with parchment. Set aside

Remove 1 roll of dough from the fridge. Unwrap, and begin cutting 12-16 even slices. Place on baking sheet about 2 inches apart. Repeat with second roll.

Bake for 12-15 minutes, or until the bottoms of the cookies have turned golden brown. Transfer to cooling rack and let completely cool.

Melt 6 oz of white chocolate over a double boiler. Dip half of each cooled cookie into the chocolate and place on parchment to dry. You can add coarse sugar, sprinkles, or candy cane pieces.