1 (28 oz) canned plum tomatoes, with their juice .
2 tbsps olive oil .
2 tbsps unsalted butter .
2 c sliced yellow onions (2 onions) .
1/4 tsp crushed red pepper flakes .
3 lbs ripe plum tomatoes, cut in half
Directions
Step #1 Preheat the oven to 400F degrees F.
Step #2 Toss together the tomatoes, salt, 1/4 c olive oil, & pepper.
Step #3 Spread the tomatoes in 1 layer on a baking sheet & roast for 45 mins.
Step #4 In an 8-quart stockpot over med-heat/flame, saute the onions & garlic with 2 tbsps of olive oil, the butter, & red pepper flakes for 10 mins, until the onions start to brown.