Let Q be the number of quiches they have to make.
The cost to make the quiches is 30 + 0.50Q dollars
The revenue from selling the quiches is 2Q dollars.
To break even, the cost of making the quiches must equal the revenue from selling the quiches.
So 30 + 0.50Q = 2Q.
Subtracting 0.50Q from both sides gives 30 = 1.5Q.
Dividing both sides by 1.5 gives Q = 20.
They have to make 20 quiches to break even. Answer: \boxed{20}.