Combine butter and granulated sugar in a large bowl. Beat with an electric mixer set at low speed until creamy.
Add flour to butter mixture and mix well. Beat in egg yolk and vanilla extract. Spread in prepared baking pan.
Beat egg white in a small bowl until foamy. Spread on top of dough with a pastry brush. Sprinkle the almonds and tinted sugar on top.
Bake until lightly browned, about 25 minutes. Cool in the pan on a wire rack. Cut into squares.