If you want a lightly salted rim, rub a grapefruit wedge around the glass lip, dip the rim into a plate with flaky sea salt (about 0.25 tsp) and set aside. Chill the glass briefly in the freezer or fill with ice water while you prepare the cocktail.

Grill garnish

Slice one grapefruit thinly into a wheel. Heat a grill pan or skillet over medium-high heat and sear the grapefruit slice 20–30 seconds per side until caramelized and slightly charred. Set aside to cool.

Mixing

Fill a cocktail shaker with crushed or cubed ice (about 1 cup). Add 2 oz blanco tequila, 0.5 oz añejo tequila, 0.75 oz fresh lime juice, 0.5 oz fresh grapefruit juice, 0.5 oz agave syrup, and 0.5 oz orange liqueur to the shaker.

Add 2 dashes of Angostura bitters to the shaker. Secure the lid and shake vigorously for 12–15 seconds until the shaker is frosty and well chilled.

Fine-strain the cocktail into the prepared chilled glass over fresh crushed ice or a large ice cube, depending on preference.

Finishing

Express the oils from a grapefruit twist over the drink by holding the twist skin-side down about 2–3 inches above the surface and giving it a firm squeeze, then run the twist around the rim and drop it into the glass.

Float the grilled grapefruit slice on top as garnish and add a single dash of Angostura bitters on the foam or surface for aroma (if any). Serve immediately.