Begin by toasting the pecans. Preheat your oven to 350°F (175°C). Spread the whole pecans in a single layer on a baking sheet. Toast them in the oven for about 8-10 minutes, stirring once halfway through. Keep a close eye on them to prevent burning. The pecans are done when they're fragrant and slightly darkened in color.

Remove the pecans from the oven and let them cool for a few minutes. Once they're cool enough to handle, roughly chop them into smaller pieces. Set aside.

In a medium saucepan, combine the maple syrup and water. Place over medium heat and bring to a gentle simmer, stirring occasionally.

Add the cubed butter to the simmering syrup mixture. Stir continuously until the butter has completely melted and incorporated into the syrup.

Once the butter has melted, add the chopped toasted pecans to the saucepan. Stir to distribute them evenly throughout the syrup.

Reduce the heat to low and let the mixture simmer gently for about 5 minutes, stirring occasionally. This will allow the flavors to meld and the syrup to thicken slightly.

Remove the saucepan from the heat and stir in the vanilla extract.

Add a small pinch of sea salt and taste the syrup. If desired, add more salt in tiny increments until you reach your preferred balance of sweet and salty.

Let the syrup cool for a few minutes before serving. As it cools, it will thicken slightly.