This has been on the whiteboard for a while: cajeta with lavender. When I finally got round to it -- when I finally remembered to buy goat's milk -- I tinkered with it a bit beyond just the use of the lavender.
Cajeta is just like dulce de leche, but using goat's milk in whole or in part. I think you're missing out if you don't use 100% goat's milk -- it contributes a very obvious "goatiness," one that's familiar but distinct from the goatiness of goat cheese, if that's your only previous experience with goat's milk. It was one of the things I thought of pairing lavender with when I first picked some up -- last summer. Told you it'd been on the whiteboard a while.
To one quart of goat's milk in a pot over medium heat, add one cup of sugar and stir until dissolved and warm. Add about a teaspoon of lavender and the zest of two bitter oranges and one yuzu (substitute other citrus as needed). Add 1/2 teaspoon baking soda and stir until it stops foaming, which may be a few minutes. Add half a bottle of Dogfish Head Palo Santo Marron and cook for an hour or two, stirring periodically, until you have a thick but pourable caramel. (Towards the end, before it's too thick, strain it through a sieve -- but if you forget, you can still strain it later.)
That's a pretty intense combination of flavors, on the face of it, and it may sound like a mishmash, but what you end up with is a somewhat tangy caramel with big floral notes (from the yuzu as well as the lavender) and a nice solid base.
What do you do with it? Well, my favorite thing to do with caramel is salted malted caramel orange ice cream:
Combine caramel and heavy cream until appropriately sweet, and add a healthy pinch of salt, or big fleur de sel salt flakes. Thin with a little milk -- very little! -- and add a few spoonfuls of malted milk powder until the maltiness is correct. Keep in mind that both flavor and sweetness will be dulled when the ice cream is frozen. Whip to stiffness (that's what she said) and freeze.