[Snowcake]

Primarily, it's a grammar thing, dante.

There might be different shades of meaning.

Fresh tomatoes are the secret to (the) making (of a) good meal.

Fresh tomatoes are our secret when we set out to make a great meal.

'We' set out to make a great meal. Thus, we take the first steps towards the goal (to achieve it) of making a great meal, and using tomatoes are part of the first steps.

Thank you, David, 'my grammar man'.