Place 0.5 cup torn day-old croissant pieces in a clean jar. Pour 4 oz Bacardi rum over the crumbs, seal, and swirl to ensure pieces are submerged. Let infuse at room temperature for at least 2 hours for a light note or up to 12 hours for fuller croissant/butter flavor. Shake the jar gently every hour.

After infusion, strain the rum through a fine mesh strainer or cheesecloth into a clean container, pressing gently to extract liquid. Discard solids. Measure out 1.5 oz of this croissant-infused rum for each cocktail; reserve extra for additional drinks.

Almond Whey Milk (make just before serving)

Combine and chill

In a small jar or mixing cup combine 2 oz whey, 1 oz unsweetened almond milk, 0.25 oz simple syrup (or maple syrup) and 0.5 oz aquafaba (if using). Seal and shake vigorously for 20–30 seconds until slightly frothy. Chill in fridge or an ice bath for a few minutes to keep cool prior to finishing the cocktail.

Taste and adjust sweetness; whey is tangy — add up to another 0.25 oz syrup if you prefer sweeter foam. Keep refrigerated and use within a few hours.

Cocktail Build & Finish

Mix

Fill a cocktail shaker with ice. Add 1.5 oz croissant-infused Bacardi rum, 0.5 oz sweet vermouth, 0.5 oz sherry (amontillado/oloroso), and 0.75 oz Mr. Black cold brew liqueur. Stir or shake lightly depending on clarity preference: stir for 20–30 seconds in a mixing glass for a silkier, clearer drink; shake hard for 10–12 seconds if you want more chill and dilution and a slightly clouded finish.

Double Strain & Serve

If shaken, double strain into a chilled coupe or Nick & Nora glass using a fine mesh strainer over the primary strainer to remove tiny ice shards and any solids. If stirred, strain into the glass over no ice or one large ice cube per preference.

Top with Almond Whey Milk

Gently spoon or pour 0.75–1 oz of the chilled almond whey milk mixture atop the cocktail. For a layered look, pour over the back of a spoon. If you want more foam, give the whey mixture another brief vigorous shake immediately before topping.

Garnish & Finish

Express an orange twist over the drink to release oils and drop it in or rest it on the rim. Lightly grate a pinch (about 0.5 tsp) of toasted almond or reserved croissant crumb over the foam for aroma and texture. Serve immediately.