As the others have said, dust one end and offer the undusted end. Mine tend to pause when they get to the point where they can taste the powder, but then decide that it's easier to keep going than spit it out. I also offer them an undusted piece of food first, just to get the feeding response going.

I also have some multivitamin powder, which smells stronger, and have had less success with that even using the same method as I use for Ca. It seems to be strong enough that they are put off taking even the undusted end (other than a couple of my girls that I'm entering in the Olympic 2 minute eating race - they eat anything).