Use to make Marque chef Mark Best's "Risotto" with Squid, Shrimp, and Curry Leaves.
Heat olive oil in a large saucepan over medium-high heat. Add shrimp shells and heads, onion, garlic, celery, carrot, chile, and tomato paste; cook, stirring, until vegetables are golden. Add chicken stock and bring to a simmer; simmer for 30 minutes.
Strain mixture through a fine mesh sieve into a medium saucepan; discard solids. Place saucepan over medium-high heat and cook until reduced by half. Use immediately or cool and keep refrigerated in an airtight container until ready to use, up to 3 days.