Preheat your oven to 275°F (140°C) for fan-forced or 320°F (160°C) for conventional ovens. Line two cupcake tins with liners. In a large bowl, whisk together the flour, sugar, baking powder, and salt. Add the softened butter and mix until the mixture becomes crumbly.
In a separate bowl, whisk the eggs, milk, oil, yogurt, tequila (if using), and vanilla extract until combined. Divide the batter into two equal parts;
add pink/red food gel and strawberry flavoring to one portion, and yellow food gel and mango flavoring to the other. Pipe alternating layers of the strawberry and mango batters into the cupcake liners. Bake for 40 to 50 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cupcakes to cool completely on a wire rack. Prepare the buttercream and split it into two portions;
add pink/red food gel and strawberry flavoring to one, and yellow food gel and mango flavoring to the other.
Lightly dip the cooled cupcakes in water, then roll them in granulated sugar to create the appearance of a margarita glass rim. Finally, pipe alternating swirls of the strawberry and mango frosting onto each cupcake. Garnish with a lime wedge and a strawberry half for a fresh finishing touch.