Butter an 8x8 baking pan, line the bottom with parchment and butter the parchment as well. Don't worry if the parchment pops up a bit, the weight of the caramel will press it back down.
In a small saucepan, heat the cream with the vanilla over medium heat until it comes to a simmer.
Reduce the heat to very low and keeping the cream hot.
Heat the sugar with the honey in a 4 quart or larger saucepan over medium high heat, stirring occasionally with a long handled wooden spoon, until the sugar is mostly dissolved and it starts to boil, 4 to 5 minutes.
Stop stirring and brush down the sides of the pot with a clean pastry brush dipped in water to dissolve any clinging sugar crystals.
Clip a candy thermometer to the pot and let the mixture boil, without disturbing the bubbling sugar, until it reaches 305 F., 2-5 minutes. Rinse any clinging sugar off your spoon and dry it with a towel.
Add the 3 Tablespoons butter and the salt. Slowly stir in the warm cream. The mixture will boil furiously and bubble up considerably as soon as you begin adding things, just keep slowly and steadily pouring in the cream and stirring. By the time the cream is added, the temperature of the mixture will have started to drop. Continue stirring, watching the thermometer carefully, until the temperature is back up to 250°F and then take the pan off the heat.
Immediately pour the hot caramel into the prepared pan.Do not scrape the pot. What sticks to the pot should stay in the pot.
Set the pan on a rack in a cool part of the kitchen. Do not disturb until the caramel is fully cool and set, about 5 hours, preferably overnight.
Run a table knife about the edges of the pan and turn the caramel out onto oiled cutting board. Peel off the parchment.With a chef's knight, cut the caramel into 100 squares ( about 3/4 inch each) and wrap them snugly into cellophane or other candy wrapper.