Adapted from Bar Chef: Handcrafted Cocktails by Christiaan Rollich and Carolynn Carreño.
Step 1Combine the gin, aperitivo, vermouth, strawberries, water, cloves, ginger and rose in a medium saucepan. Using a small knife, cut the vanilla bean in half lengthwise, scrape the seeds out of the pod, and add the seeds and pod to the saucepan.
Step 2Bring to a simmer over medium-high heat (Be careful that the flame isn’t so high that it can travel around the sides of the pan, as the alcohol in the pan will catch fire). Reduce the heat to medium and simmer gently, stirring occasionally, until the strawberries become whitish in color, about 10 minutes. Turn off the heat and cool to room temperature.
Step 3Strain the mixture through a fine-mesh sieve into a bowl, pushing down on the solids with a ladle or wooden spoon to extract every last drop; discard the solids. Transfer to a bottle or jar and refrigerate until chilled, about 2 hours, or for up to 1 month.
Step 4For each cocktail, rub the outside of an orange twist on the inside rim of a double old-fashioned glass. Fill the glass with ice cubes. Pour about 3 ounces of the mixture into the glass. Squeeze the orange twist over the cocktail to release the oils and drop the twist, shiny side up, in the cocktail. Repeat with the remaining orange twists and negroni mixture.