Combine 1 tbsp. sugar with powdered pectin. Set aside.
In a nonreactive bowl, combine the remaining sugar with the cherry tomatoes. Slice the vanilla bean lengthwise and scrape out the seeds. Add them to the tomatoes and sugar along with the bean itself. Toss until the tomatoes are evenly coated with the sugar and vanilla. Cover and let macerate for 30 minutes until most of the sugar is dissolved and the tomatoes have released their juices. Pour the mixture into a nonreactive pot and place over medium high heat. Let come up to a boil and reduce the heat to a simmer. Let the tomatoes reduce to about 3⁄4 of its original volume, about 12 minutes, stirring occasionally and skimming any foam off the top.
Stir in the lemon juice; then whisk in the pectin mixture well to avoid any clumps. Let simmer for another 5 minutes to cook the pectin.
Let cool and refrigerate or follow instructions for Canning to preserve for the winter. Fills 2 8-oz. jars.