Ingredients
2 1/2 cups all-purpose flour
1/4 cup sugar
2 teaspoon baking powder
1/4 teaspoon salt
1/4 cup butter, cubed
grated zest of a lemon
1 cup chopped fresh rhubarb
1 cup milk
1 egg
coarse sugar, for sprinkling
Directions
Preheat oven to 425F. In a large bowl or the bowl of a food processor, combine the flour, sugar, baking powder and salt. Add the butter and lemon zest and pulse or blend with a pastry blender or fork until well combined, with bits of butter no bigger than the size of a pea. Transfer the mixture to a bowl. Add the rhubarb and toss to combine.
In a small bowl, stir together the milk and egg. Add to the dry ingredients and stir with a spatula just until blended. Drop by large spoonful onto a baking sheet that has been lined with silpat or parchment and sprinkle with coarse sugar. Bake for about 20 minutes until golden. Cool on a rack.