Help! Cooking on Gas

Ok - I need help from anyone who has been cooking on gas for more than ninety minutes. I just made a simple soup (fresh sweet corn with canned crab in a seafood/paprika broth). I burned the roux WHILE watching it. How do I get the knack for this??

My oven also cooked my salami/croissant rolls in about half the time they should have. Any thoughts? (to make this easy soup accesory: open one can of croissants, roll each one with three thin slices of hard salami or pepperoni and bake as directed)

Here's approximately how you make the soup:

Melt 1/2 stick butter in sauce pan, whisk in 1/4 cup flour. Brown until just nutty smelling and a light toast color. (or darker brown if you want to do it EXACTELY as I did today) Stir in about 2 teaspoons paprika, and a teaspoon of seafood (or chicken) soup base. Add 2 cups water and stir while it comes to a boil. Add some herbs. I forget which ones. It's more about green flakes looking good than taste - the main flavor is paprika, crab and sherry.

Cut the kernels off six ears of sweet corn with your knife (or thaw a bag marked "sweet corn" from your freezer). Add the kernels to the pot.

Open two cans of crabmeat (the cheaper ones on the shelf in the grocery store - not the mortage-the-children cans in the seafood department). Add both the meat and the juice to the pot. Refrain from adding the wax paper.

Bring back to a simmer. Serve with a tablespoon or two of sweet sherry per bowl. The Southern resident also likes hot sauce for a bit more heat.