Preheat the oven to 350°F and line a muffin tin with cupcake liners, so the liners are ready for an even bake. When finished, the oven should be fully heated before batter goes in.

Whisk all-purpose flour, baking powder, and salt together in a bowl until evenly combined. You want no visible streaks of baking powder or salt.

Beat butter and granulated sugar until light and fluffy, scraping the bowl as needed. Continue until the mixture looks pale and airy.

Add the eggs one at a time and beat until each egg is fully incorporated. The batter should look smooth rather than curdled.

Alternate adding the flour mixture and the sour cream mixture (mixed with fresh lime juice, lime zest, tequila or lime juice, and vanilla extract), beginning and ending with flour. Mix just until the batter comes together with no dry pockets.

Divide the batter among the liners, filling them evenly for consistent cupcakes. Each liner should be about two-thirds full.

Bake at 350°F for 16-18 minutes until a toothpick comes out clean. Look for domed tops and a set center.

Cool the cupcakes completely before frosting. This prevents the frosting from melting and keeps the salt rim intact.

Beat cream cheese and butter until smooth for a creamy, pipeable base. Stop when there are no lumps and the texture looks glossy.

Add powdered sugar, fresh lime juice, and tequila or lime juice and beat until fully combined. The frosting should be thick enough to hold a piped swirl.

Pipe the frosting onto cooled cupcakes, using a steady pressure for defined ridges. Create a generous top layer for the salt rim to adhere.

Dip the top edge of each cupcake in coarse salt for the visible salt rim. Use light contact so the frosting remains mostly intact.

Garnish each cupcake with a lime slice right after dipping. Arrange the slice so it sits flat and shows the lime wheel.

Rest the frosted cupcakes for 30 minutes to set the salt rim and help the frosting hold its shape. The frosting should look slightly firm and less tacky.