Preheat the oven to 350°F (175°C). Line large cookie sheets with parchment paper.

In a large bowl, mix the brownie mix, flour, oil, egg, and water until well blended. Stir in the candy sprinkles.

Shape the dough into 21 (1 1/2-inch) balls and place them 2 inches apart on the prepared cookie sheets.

Press 3 Cadbury mini eggs into the center of each cookie, reshaping if necessary.

Bake for 9 to 11 minutes or until the edges are set (the center may appear slightly wet).

Let cool for 5 minutes on the cookie sheets before transferring to a wire rack to cool completely, about 30 minutes.

Store covered at room temperature.