Lemon Pannacotta with Lemon Marmalade

Let peel cool; slice lengthwise into thin strips, then crosswise in half.

In a small heavy saucepan over medium heat, stir sugar, reserved 1/3 cup lemon juice, and 1/4 cup water until sugar dissolves.

Add peel, bring to a simmer, and cook until mixture is reduced to ⅔ cup and an instant-read thermometer reads 225°F about 10 minutes.

DO AHEAD: Can be made up to 2 weeks ahead.

Cover and chill.

Pour 1/2 cup milk into a medium bowl; sprinkle gelatin over.

Let sit until gelatin softens, about 15 minutes.

Meanwhile, combine cream, sugar, lemon peel, and remaining 1/2 cup milk in a large saucepan.

Scrape vanilla seeds from bean into saucepan; add bean.

Bring to a simmer over medium heat, whisking until sugar dissolves.

Remove from heat; cover and let steep for 10 minutes.

Bring cream mixture back to a simmer.

Add gelatin mixture and stir until dissolved.

Divide among eight 3/4-cup ramekins.

Chill uncovered until panna cotta is set, at least 6 hours.

DO AHEAD: Can be made 2 days ahead.

Cover and keep chilled.

Using a small sharp knife, cut around edges of each panna cotta.

Place a small serving plate atop each ramekin and invert, allowing panna cotta to settle onto plate.

Serve with marmalade.