Sorting Right From Wrong

I’ve yet to work out what the protocol is when quoting or extracting others’ published works in this sort of online publication (which, at the moment, and indefinitely, is for my pleasure, not profit). I want to do the right thing and so, almost without exception, provide a link to either the original material or, in the case of a book, to somewhere a reader could buy it, such as Amazon.
I feel that, in such cases, I’m giving the holder of the copyright free publicity.
Is it OK for me to share, for example, quotes from Toni Morrison's Beloved? (Although it hardly needs publicity…)
There are so many extraordinary, terrible things in this book: In her foreword, she describes slavery as “a repellant landscape” and, only halfway through, I’m aghast at how little I have known of just how repellant slavery in the United States was. But there are delights here too, in the language, of course, and in one of the most enviable descriptions I have read of the pleasure of a food, of a flavour. The character “Stamp Paid” has gone searching for blackberries: “… for some private reason of his own, [he] went off with two buckets to a place near the river’s edge that only he knew about where blackberries grew, tasting so good and happy that to eat them was like being in church. Just one of the berries and you felt anointed.”
Is it OK for me to republish that quote? What if I wanted to republish an excerpt twice as long? I’d be so grateful for academic opinion on this…
And on this: is it OK for me to reproduce here the lovely cake recipe that has sent my father to the top of his nurses’ Favourite Patient List?

Nigel Slater’s Orange Frosted Marmalade Cake

175g butter
175g golden unrefined caster sugar (have never seen this in Australia: I used plain caster sugar)
a large orange
3 large eggs
75g orange marmalade
175 SR flour
Frosting:
100g icing sugar
2tbsp orange juice

Set the oven at 180 degrees. Line a loaf tin (I used a round one with no ill-effects) about 25x11x7cm deep. Put the butter and sugar in a food mixer and beat until pale and fluffy. Finely grate the orange zest. Break the eggs into a small bowl and beat them lightly with a fork. With the machine set at moderate speed, pour in the beaten egg a little at a time, beating thoroughly between each addition. Beat in the marmalade and the grated orange zest.
Remove the bowl and fold in the flour with a large metal spoon. Do this slowly, firmly but carefully, until there is no sign of any flour. Lastly, gently stir in the juice of half the orange. Spoon the mixture in the lined tin, lightly smoothing the top. Bake for 40 minutes, checking it after 35 with a metal skewer. Leave to cool in the tin – it will sink slightly. Then remove and cool completely on a wire rack.
Sift the icing sugar and mix it to a smooth, slightly runny consistency with as much of the remaining orange juice as it takes – probably just under two tablespoons. Drizzle the icing sugar over the cake, letting it run down the sides, and leave to set.

* NB: In his introduction to this lovely recipe in the The Kitchen Diaries (Fourth Estate/Gotham, 2006), Nigel Slater says that he sometimes uses orange blossom water to perfume each slice of cake. The recipe has set me off on my own trails of thought. Maybe it could have a mandarin frosting, or a blood orange one, or a guava one, or a passionfruit one. And perhaps instead of marmalade you could substitute a thick fruit compote – a Melba-ish peach and raspberry with a peach juice frosting perhaps? Or am I just delirious with tiredness?