Create MultiIndex pandas DataFrame from dictionary with tuple keys

I would create a Series using MultiIndex.from_tuples and then unstack it.

keys, values = zip(*counter.items())
idx = pd.MultiIndex.from_tuples(keys)

pd.Series(values, index=idx).unstack(-1, fill_value=0)

   b  d
a  5  2
c  0  7

---

Using DataFrame constructor with stack:

pd.DataFrame(counter, index=[0]).stack().loc[0].T

     b    d
a  5.0  2.0
c  NaN  7.0

Using Series with unstack

pd.Series(d).unstack(fill_value=0)
Out[708]: 
   b  d
a  5  2
c  0  7

Input data

d={('a', 'b') : 5,
('c', 'd') : 7,
('a', 'd') : 2}