For the pizzelles: Preheat a pizzelle maker according to the manufacturer’s instructions.
Whisk together the flour, sugar, cocoa powder, baking powder and salt in a medium bowl. Whisk together the melted butter, milk and egg in a small bowl; add to the flour mixture and whisk until blended and smooth.
Coat the pizzelle maker with cooking spray. Spoon 1 tablespoon batter into the hot pizzelle maker; cook until set and slightly darker in color, 45 to 50 seconds. Use a small offset spatula to remove the pizzelles, and immediately drape the pizzelles over the handle of a wooden spoon (3/4 inch to 1 inch in diameter) to form a taco shape; let stand until completely cool, about 3 minutes. Transfer to a wire rack and repeat with remaining batter.
For the tacos: Combine the strawberries, sugar and mint in a medium bowl; let stand about 10 minutes, stirring occasionally to dissolve the sugar.
Spoon 3 small scoops vanilla ice cream (about 2 tablespoons per scoop) into each pizzelle taco; top each with about 1 1/2 tablespoons of the strawberry mixture.
The pizzelle shells can be made ahead and stored in an airtight container in the fridge for up to a week.