Set oven to 350F Get out a 9 inch tart pan (with removable bottom preferably)

Cream the butter, sugar, and rosemary together until well combined and fluffy.

Mix in the salt and vanilla. Add the flour gradually and mix until just combined. There should be no more dry flour left, and the mixture will be crumbly.

Take approximately 1/2 to 2/3 of the dough and pat it into the bottom of the pan. I like to drop crumbles of the dough all over the bottom to distribute it before I start patting it down, this helps get the bottom covered evenly. Flour your fingertips if necessary.

Spread the marmalade evenly over the dough. Then, using your fingertips, crumble the remaining dough over the marmalade. It's ok if some of the marmalade shows through.

Bake for about 35 minutes, until the top is just starting to get a hint of golden, don't wait for it to get brown!

Let the tart cool for about 15 minutes before removing it from the tart pan. Dust with a little bit of finely minced rosemary, and slice into 8 pieces.