The actress and comedy star, 60, said she is "still reeling" from the death of her friend and co-star in February at the age of 53.
Appearing on ITV's Lorraine she said: "It's a very shocking and sad loss. She was far too young.
"And I think we're all still reeling from it a little bit.
"My memories of working with Emma are some of my most favourite memories of my whole career.
"She's a massively diligent person and much unlike Alice (Tinker)."
The actress continued: "She was also incredibly bright. Very funny, very knowing.
"And yet she was able to play somebody who was in a different world.
"She didn't play a simpleton, but someone who had a different reality.
"And she was incredibly authentic at that. I will miss that."
Dawn added: "To play a clown in a way like that takes a lot of hard work. The bit where she says 'I can't believe it's not butter' she took a whole week to learn that correctly. Because the emphasis was very important."
Born in Doncaster in 1964, Emma studied at St Mary's School before moving to Winchester and beginning her acting career in the 1980s.
From 1994 to 2007, she played the role of Alice Tinker in the BBC comedy The Vicar of Dibley and also starred in the film Notting Hill alongside Hugh Grant and Julia Roberts.
She died in February from natural causes.