How can I make onion tomato paste taste more punchy? I batch pan-fried a paste of onions and tomatoes for using them in future dishes. 

I love the flavour of garlicy onions and tomatoes! How can I make their flavour stronger?

I believe restaurants for all kinds of cuisines make use of it. 

This is how I make them right now:

I semi-grind onions, garlic and tomatoes in the ratio of 1 : (handful of garlic) : 1.

Then I roast them on the pan with a little oil starting with onions + garlic, and then once they're translucent adding tomatoes + salt. Next I roast it on a simmer for 30 minutes, stirring occasionally.

I would like to make the onion and tomato flavour a lot more punchy. How can I achieve this?
A. To make the flavor of tomatoes stronger in a sauce: 


start with better-tasting tomatoes. Depending on time of year these will often be canned. There are many reviews of canned tomatoes, so I'll not
pass judgment here but there are some excellent ones out there. 
reduce the sauce more to intensify the flavor. 
Tomatoes are an umami flavor. Adding another umami to it could intensify the flavor you're looking for (such as marmite, anchovies, etc.). 
if you want to get really fancy you can try playing around with a centrifuge such as a Spinzall. 


B. To make onions and garlic stronger you can try combining sweated fresh onions and garlic with powder. Be sure to activate the powder in water before cooking directly in fat or the flavor enzyme will be
deactivated before it can go to work.