what does "or very sometimes cook"mean?
He turned the scowl on her. “Since I qualify as a moron in this area, I should be able to handle it.”
“Great. Mind if I get a glass of wine?”
“Go ahead. You can pour me one, too. In a freaking tumbler.”
Though she found cooking relaxing, she understood the frustrations of the novice or very sometimes cook. “What inspired this do-mestic bliss?” she asked as she got out glasses—wineglasses, despite his comment.
His eyes narrowed as she slipped into the butler’s pantry for the wine. “Are you looking for a kick in the ass?”2. what does "What inspired this domestic bliss"mean?

Question

what does "or very sometimes cook"mean?
He turned the scowl on her. “Since I qualify as a moron in this area, I should be able to handle it.” 
“Great. Mind if I get a glass of wine?” 
“Go ahead. You can pour me one, too. In a freaking tumbler.” 
Though she found cooking relaxing, she understood the frustrations of the novice or very sometimes cook. “What inspired this do-mestic bliss?” she asked as she got out glasses—wineglasses, despite his comment. 
His eyes narrowed as she slipped into the butler’s pantry for the wine. “Are you looking for a kick in the ass?”2. what does "What inspired this domestic bliss"mean?

Answer

They are trying to say she understands the frustrations of a person who only cooks occasionally, but I would argue that 'very sometimes' is bad English. You could say 'a very occasional cook' but 'very sometimes' is incorrect. It was probably an attempt at humour or slang in conversation, but it still doesn't make logical sense.

'What inspired this domestic bliss?' means that the character is asking what motivated the other person to provide so many homely or comforting things (such as the wine and the meal).

Hope that helps. :)